Alexander is not your typical smuggler.

To help transport a family of six Salvadorans from a safehouse on the Mexican border to a sanctuary church in Tucson last week, he required these supplies: One banana, one half of a peanut-butter-and-jelly sandwich, two gingerbread cookies, one green Snoopy thermos filled with apple juice and "The Tale of Mrs. Tiggy-Winkle" by Beatrix Potter.

Alexander was playing hooky from nursery school so he could do his bit for the burgeoning nationwide Sanctuary Movement. He was the camouflage.

"I call these trips his learning-to-do-justice days," said his mother, Lonnie, a doctor's wife who is part of a modern "underground railroad" of church-based activists that has illegally transported and harbored more than a thousand Central American refugees in the past three years. Last month, 16 sanctuary leaders from the Tucson area, where the movement began three years ago, were indicted following a 10-month undercover operation by the Justice Department.

The leaders here say that they are obeying a higher law, that their work is saving lives and that, in the words of the Rev. John Fife, pastor of the Southside Presbyterian Church and a founder of the movement, "it must continue." And it does.

"I bring Alexander along mostly for the companionship, but there's no question he's a help," Lonnie, 31, said as the journey was to begin. "With a little kid in the car, somehow it makes it hard to think anything illegal could be going on." On this day's trip, Lonnie (all first names have been changed and those interviewed did not use last names), two other Tucson women and three of their children under age five set out for the border at 9 a.m. in a caravan of two late-model foreign imports and an old van. Eight hours later, they will have returned, dropped the refugees off at a church and headed home in time to prepare dinner.

The excursion went without incident, they said later, though not without anxiety. Their modus operandi involved, among other things, an elaborate system of guarding against possible Border Patrol surveillance by passing coded "all-clear" messages from a scout car to the two carrier cars. The signals were transmitted via roadside phone calls to a Tucson hospital, where Lonnie's husband, sometimes tracked down on his beeper, acted as the go-between.

Hospital beepers are part of the trappings of upper-middle-class comfort that made the three such unlikely -- and therefore ideal -- smugglers.

Lonnie was dressed for the adventure in a stylish brightly colored dress, designer sunglasses and silver earrings. While she wasn't reading Beatrix Potter to Alexander during the waiting periods, she was paging through her dog-eared copy of Gail Sheehy's "Passages."

The contrast between smugglers and refugees was striking. The Salvadorans were frightened, disoriented, unkempt-looking even in their newly supplied American clothes -- and they had just gone through a harrowing experience. The night before the women arrived to take the refugees to Tucson, a paid smuggler, known as a coyote, hired by the sanctuary workers for $120 to handle the border crossing, attempted to rape one of the Salvadoran women in a remote area of the Arizona desert.

"The men in the group stopped it before anyone got hurt," said Father William, associate pastor of a Roman Catholic church in the border town where the crossing occurred.

"This is the last time we'll use this guy," he continued. "He tried the same trick last week."

Before the indictments, Father William, 29, who has been involved in the Sanctuary Movement for two years, handled the border crossings himself. "I'd meet with the refugees on the Mexican side, show them a hole in the fence in the middle of town and agree to meet back up with them at a supermarket on the American side. But now with the heat on, it's too risky. So we had to hire this coyote.

"He crossed them way out of town; they had to walk three hours through the desert. He told them he'd leave them there to starve if the woman didn't submit. But they talked him out of it.

"The bastard! Now at least we know his crossing point," he continued. "We won't need him anymore."

Like most sanctuary workers, Father William sees his activity as a religious and moral duty. He also believes that working in a Roman Catholic church near the border left him no choice but to become involved.

"Refugees come knocking at your door all the time. They fear for their lives. How can you turn them away?" he asked.

The Tucson women, on the other hand, sought out an involvement in the Sanctuary Movement more actively -- and though they all did so, it was not without trepidation. Assisting an illegal alien is a felony, punishable by up to five years in prison. Conspiring to do so carries a maximum 10-year sentence. One sanctuary worker has been convicted; she did not receive a jail term.

Nevertheless, Lonnie said, "I would be lying if I said I wasn't afraid."

When she volunteered last year, she intended to offer her home as a temporary haven for the refugees, she said. She did not want to transport them, because the risk of being arrested was too high. "I've got a nice Yuppie life style carved out for myself -- power dressing, power eating, the whole bit," she quipped. "I didn't want to do anything to mess it up."

But then she started listening to refugees' horror stories. "They were just so frightened," she said. One day a hospital helicopter flew over her house, and a Salvadoran woman she was harboring grabbed Alexander and dove underneath the dining room table in terror. "I knew right then I'd have to get even more involved," said Lonnie, who has made an intensive study of religion. "I know this sounds hokey, but I feel I have a duty to honor God."

The other women tell similar tales. "People keep saying we should be patient; we should obey the law," said Martha, who used to do social work with Indochinese refugees. She is, in her 30s, the mother of several children. "Sixty thousand people have been killed in Salvador. Why should we be patient? These are human beings."

Martha said she was driven by "religious conviction and a whole lot of motherhood . . . . If I felt my children were in trouble and I was unable to help, I would want to know that there were other people on down the line who would step in."

She said she has anxiety attacks at night but keeps reminding herself that "they'd never put a mother of small children in jail -- would they?"

Marianne, who is in her 40s and was a nun for more than a decade, scoffs at the argument that the underground railroad is counterproductive because it keeps refugees from applying for political asylum. "What is it, 3 percent of the Salvadorans who apply for asylum get it?" she asked. "They practically want you to present some kind of written proof your life is in danger."

The three women make pretty fair "subversives," as they sometimes jokingly refer to themselves, though they acknowledge that their journey into the movement was not without its mishaps and trials.

On this trip, for instance, Martha wanted to go in a friend's car (she points out that she drives an old car and "believe me, I stick out") but instead of getting a station wagon, she was loaned a battered van.

"This is no good," she muttered as she dropped her two older children at school before the trip. "If anything looks like a transport vehicle, this is it." But the van was put out of commission as a carrier car during the drive down to the border. Martha said she was cited for a driving violation.

"First time in my life I've ever been in trouble with the law," she joked nervously when the three reconvened at the safehouse -- the home of a woman associated with the church -- near the border. So the group decided to make Martha's van the scout car on the trip back, while the two small wagons were transport cars.

Martha would leave first. It was her job to drive 30 miles, scour the roads to see if any Border Patrol checkpoints were set up, then phone back with an all-clear signal.

"If I say, 'The weather's fine,' that means you can come," she recalled saying after the trip. "If I say, 'The paloverdes are in bloom,' that means there are Highway Patrol out there, not Border Patrol, and you can still come but be careful. If I say, 'The weather is lousy,' stick around."

It was not clear why they used the code language; no one suspected the phone lines at the safehouse of being tapped. Nevertheless, Martha is a great advocate of caution. "I never carry anything more than one phone number on these trips," she said, "and I write it on a piece of paper small enough to swallow."

After half an hour, the call came. The message was: The weather is fine. The two carrier cars set out, 10 minutes apart ("That way, if the first gets busted, the second one will be okay," Lonnie said) each with a driver, three Salvadorans and one with little Alexander.

They took the main road back to Tucson -- past mining towns, past the stark, snow-capped splendor of the southern Rockies, past the exotic desert cactuses. Forty-five minutes into the return trip, Lonnie stopped along the road to phone her husband. He was to have received a message from Martha about "the weather" on the next stretch of road.

When he finally answered the hospital page, he hadn't received any messages from Martha. Just as Lonnie told him she was going to go for it, Martha called. The coast was clear.

From the border to Tucson (about 60 miles north), it's almost always "bueno" for the underground railroad, which is why it doesn't have to travel underground at all.

"We just don't have the manpower to set up a checkpoint and sit there on the road and wait for the aliens to cross," said Ron Moser, assistant chief of the Tucson sector of the Border Patrol. There are 120 border patrol agents in the Tucson sector. They have to cover 270 miles of border, 15 main highways and scores of desert back roads. In 1984, they caught 46,284 illegal aliens -- most of them at the border. Of those, 420 were Salvadorans, 292 were other Central Americans and the rest were Mexicans.

Apprehended Mexicans are returned just across the border. Salvadorans are sent deeper into Mexico. "We teach them the Mexican national anthem and various Mexican expressions so they can try to fool the Border Patrol if they're caught," Father William said.

After 4 p.m. the first transport car arrived at a Tucson church. The place was, unexpectedly, empty.

"Since the indictments, things have been all screwed up," Martha sighed. "We're getting new routes, training new people, and arrangements don't always work." A call was made from a phone booth down the street. Within minutes, a church worker arrived -- and soon a meal of hamburgers and fries was produced.

In the evening the family was driven to a private home. Tomorrow or the next day or the next, they ruminated, they will make their way to California to be received by a congregation that has agreed to sponsor them. The congregation had wired $1,200 to pay for the trip; $120 had been spent on the coyote and another $150 on clothes. There was enough money left for plane fare to California. Should the workers here let the refugees risk air travel, or should they pass them along over more familiar roads to other members of the underground railroad? That, it was decided, was tomorrow's question. For tonight -- Lonnie and Alexander had headed home. She'd decided to go out for dinner.