The stage was this western Virginia city of 98,000 nestled among the Blue Ridge Mountains, but it might just as easily have been Amarillo, Des Moines or Wilkes Barre as two young conservatives last week finally put their gubernatorial campaigns on the road.

In a state where party identification has been blurred almost to extinction, and in an era when personality is the dominant theme of most American elections, both Republican J. Marshall Coleman and Democrat Charles S. Robb began their race with surprising partisan appeals.

They invoked partisan rhetoric that would turn on party regulars throughout the country -- Reagan-style Republican conservatism by Coleman, and a something-for-almost-everyone Democratic smorgasbord of tax relief, equal rights and aid to education by Robb.

For Virginians accustomed to campaign differences as subtle as the drawls of a Norfolk or a Richmond accent and fearful that Robb and Coleman would be Mike-and-Ike act-alikes, there were stark differences, in style and substance, at the start of what promises to be the state's most expensive and exciting gubernatorial campaign in memory.

The Republican Party of Virginia may pride itself on a computer-based, state-of-the-art efficiency, but in the first week of the campaign Robb, the state's lieutenant governor, drew larger, although no more enthusiastic, crowds at virtually every stop.

Their respective arrivals here last week illustrated the differences. Coleman, the state's attorney general, and his wife Niki arrived Monday night on a four-passenger plane and had a quiet dinner at the Hotel Roanoke with two reporters.

Robb's entourage came Friday night aboard two chartered planes -- a dozen-member group that included two press aides, two financial advisers, and even a woman traveling companion for Robb's wife, Lynda, daughter of former President Lyndon B. Johnson. The Robbs ate in their hotel room and starred at a rousing rally attended by 300 at the Patrick Henry Hotel.

In wrapping themselves snugly within their party blankets, Robb clearly is taking the greater gamble, seeking to rebuild a Democratic coalition that has suffered 12 years of defeats in a state it once controlled.

Democrats, who view Robb's candidacy as the first step back to political power, paint this election in almost apocalyptic terms. "This is," as state Senate Majority Leader Hunter B. Andrews told a feverishly cheering Democratic crowd in Norfolk, "a campaign for redemption and resurrection and resurgence."

Coleman, 38, who seeks to cling to Ronald Reagan's still strong coattails, was equally willing to make the campaign -- one of only two statehouse elections in the country this year -- a referendum on party and national policy. He told a private audience of Republican bankers, lawyers and business people here that: "All eyes have turned to Virginia.

. . . This race will be seen rightly or wrongly as a vote of confidence in the Reagan administration and its policies."

For two young politicians who leapfrogged to the top over more party-oriented candidates by personality-oriented campaigns in 1977, the appeal to party is a novel, and perhaps dangerous, approach in a state that has no party registration and historically has given little support to national political issues.

It may illustrate what some cynics say is an attempt to draw distinctions between two candidates where none exist. "On some days," says University of Virginia political scientist Larry Sabato, "I think Robb ought to be the Republican nominee and Coleman the Democrat."

Told of Sabato's observation, Robb said in an interview last week that he has had offers from "a lot of Republicans" to join their party. But he said "i am very comfortable in the Democratic Party and my association with it. Having cast my lot, I am going to be a loyal Democrat."

But Robb, 41, who spoke publicly with a partisan fervor last week, added: "Party to me is not a philosophical matter . . . It's nonsense to think that you have to go with the Republicans because of a perception that it is the party of the conservatives."

Robb said "one of the real strengths of the Democratic Party is that it has been able to attract people of diverse backgrounds. It's not necessary to require a knee-jerk litmus test on issues. Parties ought to recruit people who can provide the most thoughtful and responsible government, who stand for principle instead of ideology."

Robb's remarks support the view of his strategists that the choice between him and Coleman will come down to which candidate is the more trustworthy.

And Robb's surrogates last week seemed more than anxious to claim their man is the better on that score. "Coleman is just a chameleon -- whatever's expedient to win, he'll do it," said House Speaker A. L. Philpott, one of Robb's chief allies. Said Robb campaign aide Jack Sweeney: "We think the campaign will boil down to whether you can trust Marshall Coleman with the sacred keys."

At the same time, Coleman began to hone in on what will no doubt become a major theme for him -- Robb's lack of experience in state government and his perceived fuzziness on issues. Whenever Coleman was asked to explain how he differed from Robb on an issue, his response almost always began: "Well, I don't really know where he stands on this or on other questions . . . ."

After listening to Robb deliver his speech in Roanoke, veteran political reporter Melville Carico adjusted his red baseball cap and suggested that "There was nothing in it anyone could argue with. But it doesn't matter a damn what he says. The Democrats want to win this one for a change."

Everywhere Robb went last week, Richmond, Tysons Corner, Norfolk, Charlottesville, Staunton, Roanoke, and Bristol, his advisers pointed to persons in the crowds they identified as conservative Democrats who had abandoned the party during the 1970s.

"I haven't seen this variety of people under one roof since 1969," boasted State Del. Alson Smith of Winchester, Robb's chief finance man, at a Charlottesville rally, where bankers, students and party foot soldiers rubbed elbows.

But there were times when Robb's advance work and careful staging backfired. Some Charlottesville Democrats grumbled about a "checklist" of necessities preceding Robb's arrival that included a water pitcher on the podium, musical accompaniment, and a "holding room" for the candidate.

In Staunton, Robb spent 15 chilly minutes posing for newspaper and TV cameras in front of a monument to John Lewis, his great, great, great, great grandfather who helped settle the Shenandoah Valley area 300 years ago.

But a few minutes later, at an indoor rally, all of that rich Virginia heritage was uprooted when, in introducing Robb, the speaker innocently mentioned that Robb is "a native of Arizona." Both Robb and his wife glared at each other and then at the speaker for having revealed a fact that is omitted from a campaign biography which begins with Robb's graduation from Fairfax's Mt. Vernon High School in 1957.

Coleman's backers downplay the importance of the campaign's opening week. "They always start out ahead," said Anson Franklin, Coleman's campaign manager, "but we seem to do pretty well in November."

Despite the smaller size of the crowds that greeted him, Coleman on the stump was more informal and better suited for small groups than Robb. The Democrat seldom ventured from his prepared text and his friend Al Smith observed, "I've never heard Chuck tell a joke in his life."

But Coleman's sharp and sometimes flippant sense of humor backfired a few times. In Roanoke, before a breakfast crowd of party loyalists, he got big laughs with a joke about his son Billy's refusal to make his bed. Then he hit a stony silence when he smilingly noted that "I've been to Roanoke in early mornings in previous campaigns and not all of you were there.

The candidates' wives are obviously going to play major roles in the campaigns. Lynda Bird, whose forceful manner and speech patterns are an instant reminder of her famous parents, demonstrated a zeal that many observers found missing in Robb's 1977 campaign for lieutenant governor.

She also brings a star quality to the hustings. Nearly every place or event reminds her of a story of her days as the daughter of the president or vice president. "It was just 20 years ago today," she told a Norfolk rally, "that I was honored to be here as your Azalea Queen."

Paul Hirschbiel, a retired banker who was chairman of the Azalea Festival the year Lynda was queen, and his wife, Mabel, said the presence of Robb on the ticket would bring them back to the Democratic fold. "We're Byrd Democrats," said Mrs. Hirschbiel, but they voted for outgoing Gov. John N. Dalton "because we couldn't take Henry Howell [the party's controversial 1977 nominee for governor] and Ronald Reagan because we couldn't take Jimmy Carter."

Several people at the Robb rally in Staunton groused that Coleman had bypassed his hometown on his initial tour. One woman said she was infuriated because Coleman's two sons live in Staunton with first wife, Maureen, a school teacher, "yet Marshall drags them to Richmond to pose for pictures and make it appear as though he and Niki are one big happy family with four beautiful children." (The other two children are Niki's from her first marriage.)

Niki Coleman is no slouch on the stump either, as Democratic House Speaker Philpott learned Tuesday when he appeared with her at a Southside Virginia women's club meeting to discuss her husband's views on mandatory prison sentencing for repeat offenders.

"She did a better job than Marshall would have," said Philpott. "I can attack him, I can't do that to her." Philpott's legislative protege, Del. Mary Sue Terry, put it more succinctly: "She killed you, Mr. Philpott."