"I just can't resist telling you this," says Ronald Reagan, as if the idea just came to him, as he looks out over the crowd at Houston's Tranquility Park one morning. "Nancy and I were campaigning earlier in the primary, doing some door-to-door work and I knocked on a door and said that I was running for president and this was my wife. He said, 'I don't know who you are.' I said, 'We're from California.' Nothing. I said, 'We used to be in pictures.' Still a blank. I said, 'My initials are R.R.' and with that his jaw dropped, his eyes popped open and he turned around and yelled into the house. 'Maw, come out here, it's Roy Rogers and Dale Evans!'"

On stage Roy Rogers and Nancy Reagan look up, register boffo surprise at the punch line, then roar with laughter.

Fort Worth Airport that afternoon. Reagan looks out at the mob at a hangar rally. "I just can't resist telling you this . . . used to be in pictures . . . my initials are R.R. . . . 'Maw, come out here, it's Roy Rogers and Dale Evans!'"

Roy Rogers and Nancy Reagan look up, register boffo surpise at the punch line, then roar with laughter.

Dallas, later that night. Eight thousand at a rally at Southern Methodist University. "I just can't resist telling you this . . . 'Maw, come out here, it's Roy Rogers and Dale Evans!'"

Roy Rogers and Nancy Reagan look up, boffo surprise, roar.

Ronald Reagan never knocked on a door once campaigning this year, according to aides, and he looks about as much like Roy Rogers as Lassie does Trigger, but never mind. It's just a trio of old actors playing their parts, yukking it up to the end of Campaign 1980, catching the fever of the moment, the taste of a possible victory.

The final hours of the Carter-Reagan campaign revealed an extraordinary study in contrast. On Reagan's plane, the post-debate euphoria escalated by the hour as pollsters and pundits played count-the-numbers. They could see a Reagan victory, possibly a history-shattering victory, with Reagan winning the electoral votes and Carter the popular vote.

Ronald Reagan, ruddy-cheeked and smiling, took off his coat, looked back at the press jammed into the plane, tossed an orange jauntily in the air, then rolled it down the aisle at takeoff.

On Air Force One President Carter, his face puffy with fatigue, his voice hoarse from countless speeches, his hands swollen and cut from the nicks of rings, remained closeted up front, never looking back at the small pool of reporters crowded into the rear, surrounded by the mementos of power -- pictures of Carter with Sadat, Carter with the pope . . .

The contrast was especially evident in the messages Reagan and Carter were sending at stop after stop. Reagan, going at a traditionally Democratic working-class ward in Bayonne, N.J.: "Now I know what it's like to pull that Republican lever for the first time because I used to be a Democrat myself. But I can tell you -- it only hurts for a minute."

And Carter, urgently rediscovering he is a Democrat, wrapping himself in the mantle of FDR and Harry Truman and JFK and LBJ -- exhorting Democrats to come home to the party. In Brownsville, Tex., Lyndon Johnson, the man Carter called a liar on Vietnam in a Playboy interview four years ago, is transformed into a "great man." Then, with an edge of desperation to his voice, Carter shouts, "Think about the prospects in your life if you wake up Wednesday morning with a Republican president in the White House." In the closing hours, even more desperate, he pleads with Anderson supporters not to "throw away your votes" by voting for the independent.

Both campaigns were in those peculiar moments, riding the tiger. Who knew if the hostage issue, which flared once again so dramatically on Sunday night, would help Carter or Reagan? Who knew if the volatile and vital undecideds would suddenly make up their minds and cast a "too close to call" election into certainty? On the campaign, it was a frenetic whirlwind. Here is a set of scenes from the final days. Twin Resignations

At one stop in Texas, Lyn Nofziger, Reagan's rumpled press aide, smiled like a Cheshire cat. He handed out a newly minted bumper sticker, one of many that surfaced after Carter's debate gaffe, referring to nuclear proliferation as Amy's chief concern. "Ask Amy -- she knows?" it said.

A reporter who transferred to the Carter campaign gave the bumper sticker to Jody Powell, standing in the sunlight at a Memphis, Tenn., rally. He quipped that Reagan could use her -- "I understand they're looking for a national security adviser." Powell was referring archly to that moment's blaring headline -- Richard Allen, Reagan's top foreign policy adviser, had stepped out of the campaign amid reports that he had used his White House post during the Nixon administration to obtain business contracts for himself.

But Powell had his own campaign-aide resignation to explain after Carter adviser Frank Moore spouted off about the ayatollah's alleged cancer condition. Powell said the decision to stop campaigning was Moore's.Obviously, he can't campaign because all the press wants to write about is -- What's a euphemism for the ayatollah's colon? In any case he can't talk about the issues."

That night, in a hotel bar, when ABC-TV correspondent Sam Donaldson bellowed unmercifully, "You're gonna lose, Powell, you're gonna lose!" Powell, normally adept at the quick-witted comeback, just said, "Sam, you're crazy." A Tale of Two Texases

Reagan's rallies are a sea of all-white faces, red-white-and-blue sequined drum majorettes, pounding high school bands, American flags, stomping, shouting enthusiasm. Reagan's rehearsed ad libs fit the events -- which can only be called "staged reality." The staging -- mammoth American flags, Reagan's characteristic head wagging and aw-shucks grin, his "GE Theater" delivery -- is all by design. But the reality is in the reaction of the faithful. They roar with true emotion to the canned one-liners that often uncannily sum up widely held opinions. Reagan has just the right slogan for those who view Carter as a cold, not overly skillful technocrat: "He's like the guy who can name you 50 parts of a car -- he just can't drive it or fix it." Eight thousand in SMU's Moody Coliseum shout with real anger when Reagan says the real reason oil imports have declined in recent years has nothing to do with Carter's energy program but has a lot to do with the "recession Carter caused. Factories that are closed don't use energy and employes that are laid off and don't have jobs don't use gasoline to drive to work every day."

His messages that corporations can do it better, that we are an energy-rich nation hamstrung by environmental regulations, is soothing elixir for the wealthy who jam the coliseum in oil-rich Dallas. "We sit on enough nuclear energy . . . and yet we canceled the building of 42 nuclear power plants!" is drowned in sustained applause. To the families who are sending their children to private schools like SMU, Reagan charges that the day when "all of education in the United States is tax-supported and public, that will be the day that academic freedom disappears from the United States."

Reagan's broader appeal touches a chord from Texas to Philadelphia. Over and over it detonates a thundering, almost frightening response as Reagan plays to a fear and helplessness, a visceral hatred of burgeoning federalism. If elected president, he promises, he would become chief surgeon: "I would take the lead in getting the government off the backs of the people of the United States and turning you loose" in what he promised would be a "decade of deliverance."

Carter's crowds are mostly a mix of blacks and Hispanics, working-class and liberal Democrats, what is left of the old FDR coalition. The blacks express a real and abiding fear of Reagan. "He would do nothing for us," said a black woman in Brownsville. "If you be poor, Reagan don't hear you no how," said a black man standing at a Carter rally in front of the governor's mansion in Jackson, Miss. For many interested in social programs, the poor, the elderly, there is also concern. A sign at one Carter rally in Abilene said "Reagan: Fascist Gun in the West."

Carter seeks to voice those concerns at a rally in Houston filled with middle-class and minorities and Spanish-speaking people. They must be energized for him to have any hope of wining Texas. And so the tired voice hammers on: Reagan is "against national health insurance . . . This year he proposed the minimum wage be abolished . . . the Reagan-Kemp-Roth proposal, as Business Week said, "would cause an inflationary explosion that would destroy this nation's economy. It would improvish every single person in this country living on a fixed income." But Carter has no style, or, as one young Chicano college student says, "even no rhetoric," and people on the fringes of his crowds drift off.One man loping down the streets of Cowtown outside Dallas, as the president spoke in the square, said he was going off to get drunk. Asked who he would vote for, he replied, "Willie Nelson."

Three construction workers placed their cowboy boots on a fence, leaned over and said they thought Reagan would take Texas for sure. "This is conservative, Bible Belt. Hell, this section right here is a Chicano barrio. That's why Carter's here -- and not on the other side of town where all the rich Republicans live." The Press

For months they have been encapsuled in the aluminum womb of the press plane. Frantically writing stories on deadline, phoning in from the plane, chasing rumors, getting into good-natured, drink-sodden arguments with aides, forming a rare closeness not unlike comrades at war. The reporters are observers, but they are also citizens who cast votes. And so theirs is a special dilemma. Some, in fact, simply don't vote for president.

This year, the perceived character of the candidates presents a troubling dimension to reporters. Many covering Carter do not like him, view him as cold and unfeeling.One reporter who has covered him for five years says, "I have never been asked up front on Air Force One; very few have. He doesn't like us and we don't like him." Another says, "Everyone hates to get pool duty and fly on Air Force One. It sucks. Powell comes back and talks sometimes, but they don't want us there. They make you feel like a wino if you take a glass of wine."

By contrast, levity reigns on the press plane, which follows along everywhere behind Air Force One, and is packed with 110 media types. On Halloween, a Secret Service agent and assorted stewardesses and reporters are marching down the aisle in Halloween masks, to wild applause from the rest. One reporter takes off his mask, settles down and says, "Carter just lacks the essential ingredient of humanity. I've become convinced he doesn't really like people. He's a technocrat who stumbled into politics and found a formula for getting elected. But, hell, I cannot bring mayself to vote for Reagan. He's a political tool of a lot of ideologically bad people and he lacks intellectual depth."

The dichotomy is that many Democrats in the press like Reagan the person. he appears easygoing and expresses genuine concern one on one. No one was more upset than Reagan when an overworked aide fainted the other day on the plane.

"But," says a reporter who has covered him a long time, "he reminds me of the guy who would give you the shirt off his back -- then cut federal school lunch programs." Another says, "His is a personal concern coupled with a political insensitivity. Sure, he'd be the best guy to go out to dinner with, but if you care about the social things I do, I can't see him president." Another chimes in, "I was there in the 1976 Florida primary when he switched his standard speech on how galling it is to be in a supermarket checkout line, buying hamburger, while the person in front of you was buying T-bone steaks with food stamps. Only this time, he substituted, for 'people,' 'strapping young buck.' My jaw dropped a foot. He's not inherently evil, he fans the flames with those kinds of lines. I can't believe he doesn't know what he's doing." Another says, "He's very shallow. What we'll be getting is the old Nixon crowd: Shultz, Greenspan, Kissinger, with Reagan mouthing the lines."

Many of the Carter second echelon are liked by the press, but few of the senior staff are. "I'd like to see those guys humbled, but I'm not sure it's worth four years of Loony Tunes Republicanism," said one who will vote for Carter. Still others, even those with a long history of liberal Democratic leanings, say such things as, "Reagan couldn't be worse than Carter." "More contrasting views will reach Reagan through Messe [Ed Meese, a top aide] than ever reached Carter through Ham Jordan. And they don't get mean, like the Carter crowd does, when you write a tough story."

One cynic said, "Just wait till they get in the White House." Hecklers and True Believers

Reagan is followed by a small band of pro-ERA people and anti-nuke demonstrators. Carter is trailed by the Right to Life and far-right religious groups and clusters of people with blue-and-white Reagan/Bush signs. Christians for Reagan take out ads saying Carter approves the "lesbian-backed anti-family ERA" and supports homosexuals.

In Jacksoin, Miss., a Ku Klux Klan leader takes out an ad denouncing Carter before his appearance. Then, at the rally, about six good old boys -- one of whom says he thinks the Klan "done a lot of good things" but refuses to say if he is a member -- set up a raucous counter-shouting to Carter's speech. Nearby blacks look on angrily, but silently. One of the hecklers, with stringy blond hair, grins and says, "Hey, lets all yell white power." His friend, holding an anti-Carter sign, shouts, "I got holes in my shoes because of you. Hey what about them taxes?" Carter mentions defense and the word is back: "Born-again Commie!"

The other side is heard outside a Philadelphia senior citizen's meeting. "A vote for Reagan is a vote for war," shouts a demonstrator, waiting for Reagan to emerge. A scowling, intense man from Hoboken who works in a factory and organized the group, holds a 10-foot sheet saying "Anti-Worker, Anti-Consumer, Anti-Poor." He shouts the slogan over and over. Then an older man starts to light the sheet with a cigarette lighter. The young man drops his end of the sheet and races over and shoves the man away. Another older man shouts, "Why don't you get a job?"

"I have one," spits back the demonstrator.

A few hours later, six pro-ERA demonstrators find themselves high in the rafters surrounded by about 3,000 Reagan supporters at a massive rally in Upper Darby. "Pennsylvania is the key" to win the election, shouts one speaker. 'We will deliver that key. This is REEEEEGAN country," Reagan hits hard on the grim statistics: "More than 440,000 in Pennsylvania are out of work . . ." Meanwhile the six start chanting "ERA now." Two men race out of their seats and knock the signs down. One rips up a sign and stomps on it. The police look on for some time and then wander up to remove them. As the officers go past, an older woman with carefully coiffed, blue-rinsed hair says, "They're crazy," then adds in a hard voice to the police, "You should have left them there." The Staff

A quasi-genial, quasi-sparring relationship is established on long campaigns between staff and press, as the staff tries to float its candidate's position and the media folk try to find out anything they're not supposed to know. Aides in both camps have been known to freeze out reporters who do tough stories.

Stu Spencer, a tough pragmatist and Reagan strategist, was on the opposite side four years ago, working night and day on Ford's campaign. He joined Reagan in the fall and is credited with stabilizing the campaign and keeping the candidate relatively gaffe-free. Spencer was not there during the "killer trees" period when Reagan said trees caused more pollution than cars.

Four years ago, Spencer's tone was belittling when he spoke of Reagan. "Ron's a fine guy, but this is the big leagues. There's no way the moderates of New York or Ohio or anywhere are going to go for him." Today Spencer still says, "I would have liked to have Ford run," but he is comfortable with Reagan. "Carter's been a crappy president."

Spencer, exhausted but happy, is sitting in the plane while his candidate is revving them up at an airport hangar rally. Most polls showed Reagan winning the debate. "We set Carter up good. They didn't think we were going to debate and we purposely started leveling off -- then bam, we hit them." His confidence oozes as he looks at the major states Carter won four years ago that Reagan is now expected to win. "We've got so many options Carter doesn't have."

Meanwhile, in the Carter camp, Greg Schneiders leans on a TV trailer in Memphis, Tenn., also putting an optimistic face on it all; the Carter camp is hoping for a Dewey-Truman rerun. "The undecideds feel serious dissatisfaction with Carter but have a concern about Reagan -- war and peace, his age, intelligence. We feel fairly optimistic that many will go with the known, the safest." Later, on the plane, Powell tells the press that Carter's campaign has lost some momentum after the debate. (It came out momentumpause in the jocular pool report.) Like nearly everything Powell says, that remark was not offhand, but by design, made in hopes of revving up the troops to work harder for Carter. Friendly Skies

Slap-happy fatigue turns manic in the final days on the campaign planes. In the Carter press plane, reporters are betting on everything -- the exact second the plane will land, the combined age of nine stewardesses. Shouts greet every announcement from the staff.

Food and booze are passed constantly on both planes, and the thought occurs that it is a sneaky campaign strategy to keep the press from thinking very well, if at all.

In one day on the Carter plane you could consume: orange juice, grapefruit juice, Bloody Marys, doughnuts, coffee, tea, milk, eggs rancho huevos, fruit cup, biscuts and honey, cold ham and cheese in pita bread, cherry tomatoes, a mint, macadamia nuts, pretzels, burriot, guacamole dip, apple, beer, chocolate pudding, salad, pinto beans, barbecued beef, rice, roll, cake, crackers, wine, champagne, assorted booze.

And another day on the Reagan plane: doughnuts, coffee, orange juice, steak, hash browns, grits, eggs, fruit cup, coffee, tea, milk, lobster and shrimp, rice, peas, salad, chocolate pie, lasagne, salami salad, cannoli, fortune cookie, pretzels and potato chips, fruit plates, lo-cal peach yogurt, cream cheese and date-nut bread, cantaloupe, crackers, the usual assorted booze.

Take that, Weight Watchers, Inc. Sirens and Song

One of the final journeys of the Reagan plane. On takeoff, the recorded voice of Willie Nelson blares "On the Road Again." As the plane pitches on its climb, a cameraman surfs down the aisle on one of the plastic what-to-do-in-case-of-an-emergency airline cards. Whistles, kazoos, sirens go off. Roy Rogers lopes through, singing, "Happy Trails to Yew-who-who," and signs not only his autograph on press badges but that of his embalmed old buddy Trigger. Nancy Reagan does her number -- rolling an orange down the aisle -- and everyone cheers, even those who think the ritual pretty silly.

By tonight, the O. & W. (the oldest and wisest) as he is known in pool reports (written more for peer edification than for the public) will or will not be the next president of the United States.

But one thing is finally, perfectly clear. The longest, most media-saturated presidential campaign in anyone's memory has, believe it or not, irrevocably come to and end.