SPEARFISH, S.D. -- As his 15-car motorcade snaked through the Black Hills last week for campaign stops in three remote ranching towns, each with populations under 5,000, Vice President Bush was navigating more by calendar than road map -- and a perilous calendar at that.

Bush was trolling along the back roads because his campaign, he acknowledged, "is a little behind in this state." Playing catch-up is an anomalous position for a front-runner. But it's one Bush faces in roughly half of the 13 states that will hold contests before "Super Tuesday," March 8, in the reshuffled and front-loaded Republican lineup of primaries and caucuses.

"The early states are wrong for Bush -- too much Farm Belt," said Ed Rollins, presidential campaign chairman for Rep. Jack Kemp (R-N.Y.). "If anything gives {Senate Minority Leader Robert J.} Dole the reality of being a viable option, it's the calendar. Bush could very well lose four straight going into New Hampshire."

This rejiggered Republican calendar is an underreported phenomenon of the 1988 campaign. Attention has been riveted to the familiar "gate states" of Iowa (Feb. 8) and New Hampshire (Feb. 16), to the bitter haggling over party rules in Michigan (Jan. 29-30), and to the big new kid on the block, Super Tuesday, which will see 20 states -- 14 of them in the South or along its border -- hold events on a single day.

No one disputes the Bush campaign's claim to an organizational edge in the Super Tuesday states. Before heading south, however, Bush first must survive a mixed bag of other contests, dubbed by political wags the "Lesser Antilles," that have quietly elbowed their way into the hunt. There are 11 "Lesser Antilles" (not including Iowa and New Hampshire) on the Republican side, compared to four on the Democratic side. The Democratic early action appears less fateful -- there's less of it, and there's no front-runner to be tripped up.

Bush, on the other hand, will be hounded early by bad geography and by a tag-team of challengers who have each picked their best spots for an ambush. It's the familiar front-runner's squeeze -- only he is expected to run well everywhere -- and it's at the core of each of his rivals' strategy for an upset.

Nomination contests are dynamic and sequential affairs, in which one week's odds get scrambled by the previous week's vote. Early losses can be the most treacherous.

"If you are the front-runner and you don't do well early, your support gets very soft very fast," said William E. Brock, chairman of the Dole campaign, "especially if the whole basis of your appeal is winability."

"He doesn't have the philosophically committed base or the charisma to hang on to his people through a lean start," said Charlie Black, Kemp's campaign manager. "They aren't the types who jump off cliffs."

"I have sat here for three years and heard these guys underestimate George Bush," retorted Lee Atwater, Bush's campaign manager. "If they keep doing it, we'll be in fine shape."

Atwater argued that resiliency

is the trait Bush has shown plenty of this year. He clicked off his list: way ahead in national polls, fund-raising, organization and endorsements; did better in the early debates than had been predicted; made it through Iran-contra; will get a big boost as the only Republican contender actively supporting the INF treaty.

Yet there's trouble for Bush here in South Dakota (Feb. 23) and in Minnesota (same day), in Hawaii (Jan. 27) and Michigan (Jan. 29-30), and in Kansas (Feb. 1-7) and Iowa (Feb. 8). "We'd like to win at least half of the states before Super Tuesday, and we think we can," said Brock, who knows much of the early opening for Sen. Dole (R-Kan.) comes because the contests are being waged in his midwestern back yard.

Indeed, of all the early states, Bush has a clear early edge only in Maine (Feb. 26-28), where his summer home and Yankee roots give him something akin to favorite-son status, and in New Hampshire, where he has a bulge in the polls and a pledge from his state chairman, Gov. John H. Sununu (R), to make it hold up even in the face of a "worst-case" string of losses beforehand. (New Hampshire, however, has a history of being inhospitable to front-runners in general and to Bush in particular.)

The New Hampshire primary remains first in the nation. Four caucus states precede it. The first is Hawaii, which Dole targeted early by lining up the support last February of Rep. Patricia Saiki, the first Republican to represent the state in Congress. Bush is working legislators and party leaders.

Michigan comes next; it has turned into a black hole for Bush. When Michigan was a primary state in 1980, Bush carried it 2-to-1 over Ronald Reagan. This time, it adopted a unique caucus-convention system in which the only people who will be able to select the state's 77 national delegates next January are precinct delegates elected in caucuses held in the summer of 1986. Marion G. (Pat) Robertson's forces scored a coup in those elections, winning about as many delegate slots as Bush, with Kemp running a distant third and everyone else choosing not to compete.

The Robertson and Kemp forces have since forged an alliance in Michigan, which appears to have the strength to win a majority of national convention delegates. A series of bitter rules fights (the Bush forces just won the first round of a court case) have muddied the water, however. Many observers now say they believe a credentials fight could be carried on all the way to the GOP convention in New Orleans. For now, the best Bush probably can hope for is confusion, not an outright win.

Next comes the Kansas caucuses (Feb. 1-7), where native son Dole does not expect a serious challenge. After that is Iowa (Feb. 8), where Dole has moved well ahead of Bush in the most recent poll of likely GOP caucus-goers, and where the wild card remains Robertson, who is organizing through a network of evangelical churches.

Iowa is the closest thing to a "must-win" state for Dole. If he wins, he is hoping to take his momentum into New Hampshire, where he has the support of Sen. Warren B. Rudman (R), but where he is also being hammered regularly as a closet taxman by the likes of Kemp, former Delaware governor Pierre S. (Pete) du Pont IV and du Pont's most important supporter anywhere, Nackey Loeb, publisher of the Manchester Union Leader.

After New Hampshire come South Dakota and Minnesota. The Bush forces have all but chosen to opt out of Minnesota, a caucus state filled with conservative activists, where both Kemp and Robertson are strong.

But the Bush forces do not want a double loss on that day, so they have decided to tackle Dole head-on in South Dakota. A barrage of television commercials -- Bush's first in any state -- began running here late last week. The vice president's trip to Spearfish (pop. 4,661), Sturgis (pop. 4,536) and Belle Fourche (pop. 4,236) last Wednesday was his sixth into the state since the summer. The small-town itinerary is a "genuis stroke," said state GOP executive director Bill Protexter, that humanizes him in a way that airport news conferences cannot.

"They have upped the ante for themselves here," said Dwight Adams, Dole's campaign manager in South Dakota. "Six months ago, there were rumors Bush would bypass the state. Now, if Dole wins, they can't say they didn't try."

Adams was the 1986 campaign manager for popular new Gov. George S. Mickelson (R), who has endorsed Dole. Their organization is already functioning at a precinct level. At county GOP caucuses held last week, Dole forces elected 181 county delegates around the state, compared to 150 for Bush, 76 for Kemp and 67 for Robertson. The delegates have no impact on the primary, but represent a rough show of organizational strength.

Robertson, here as elsewhere, is a wild card.

In Wyoming, Dole appears to have an early start on the field, but Atwater promises a "serious effort" by Bush.

On the Democratic side, Massachusetts Gov. Michael S. Dukakis is judged to be ahead in South Dakota, but some local politicians complain of arrogance and say he's too sophisticated for the state. Rep. Richard A. Gephardt (Mo.) started strong, but according to local politicians and observers, he has slumped. Illinois Sen. Paul Simon's campaign says it will saturate the South Dakota television market with a late buy. Jesse L. Jackson is trying to appeal to disaffected farmers and labor.

In Minnesota, a recent poll of Democratic-Farmer-Labor voters shows Jackson at 23 percent and Dukakis at 20 percent, with Simon at 11 percent and Gephardt at 7 percent. Dukakis has the support of St. Paul Mayor George Latimer as well as Kevin McHale, the Boston Celtics basketball star and University of Minnesota alumnus. Simon has a "Committee of 1,000" led by Minneapolis Mayor Don Fraser.

Gephardt and Dukakis are organizing in Wyoming, and so is Sen. Albert Gore Jr. (Tenn.), who has the support of former governor Ed Herschler. It's also the only early state except Iowa and New Hampshire that former Arizona governor Bruce Babbitt is contesting.