KENNEBUNKPORT, MAINE, SEPT. 4 -- At this early stage of the GOP presidential campaign, Vice President Bush enjoys a number of advantages: a strong lead in fund-raising; the visibility of his office; the allegiance of many GOP activists and officeholders that comes from a long political career in government and the party.

Not to mention the harbor seals that frolic in the Atlantic off this southeast Maine community where the Bush family has summered for three generations.

The Bush campaign played the seals card this week as the vice president hosted convivial gatherings with supporters and would-be supporters from around the country at his ocean-front vacation compound. Comfortably housed at a posh seaside inn down the road, the guests were bused to the Bush summer residence for barbecues, boat rides and low-key politicking.

"Our people were clearly wowed," said Rep. Harold D. Rogers (R-Ky.) as he came ashore from a seal-viewing spin aboard Bush's sleek blue and white speedboat. "To be invited to the vice president's home on Labor Day weekend for a cookout is a lifetime experience," said Rogers, one that would "intensify the commitment and devotion" of the 43 Kentucky Republicans who, like the other guests, made the trip at their own expense.

Paul Coverdell, the minority leader of the Georgia State Senate, and the head of the Bush campaign's southern steering committee, agreed. Asked about the political -- as opposed to the recreational -- value of the sessions, Coverdell said they "energize people and send these folks home feeling they've been brought up to date."

For the Bush campaign staff, it was a week to gird for crucial tests for their candidate over the next two months. By the end of October, Bush's political strength will be tested in a serious party squabble in Michigan and a straw poll in Iowa. His ability as a campaigner will be judged on the message he offers in his formal announcement, expected by the end of the October, and in his performance in the first full GOP debate on Oct. 28.

The entire top echelon of the Bush campaign -- strategists, media advisers, finance directors, campaign managers, pollsters and assorted gurus -- gathered for what campaign manager Lee Atwater described as "the last big strategy session before the campaign begins in earnest."

"I've always felt the need to have sessions like this," said Atwater of the Kennebunkport powwow. "It's a chance to get away in a relaxed atmosphere, in the cool of the night without shells flying by you, to make basic decisions. It's going to get white hot in the next couple of months."

As a late-summer sun sparkled off waters plied by lobstermen, the Bush strategists put the finishing touches on their fall campaign plans -- honing themes, preparing for the announcement hoopla, discussing the Iowa straw poll next week and the vice president's upcoming European trip.

A key item on the agenda, as it has been for months, was defining a message that will allow Bush to reap the benefits of his seven years' in the Reagan administration while simultaneously building a separate identity. The problem for the vice president is to appear loyal but not a lap dog; independent without biting the hand that fed him.

"There is a certain record to run on, to be proud of, and he's not going to run away from that," said one senior campaign aide. "By the same token, this campaign has to be looking to the future as we move into the 1990s."

The shades of distinction, that aide said, would come in such areas as education and the environment. And with the economy fairly strong, there will be a major effort this fall to emphasize Bush's expertise in foreign affairs, once a strong point on Bush's long resume but now a qualification that has been tarnished by the Iran-contra affair.

"I don't see any polling evidence that anyone wants to undo what Reagan has done," said pollster Robert Teeter. "I don't think he is going to deviate from Reagan. It's a matter of saying here's the good things we've done and here's how we are going to build on them."

To Bush supporters from the South, that message came as welcome news. "If he appeared to distance himself from the president, it would do him damage in the South," said Lou Kitchin, a Georgian who served as Reagan's Southeast political director in 1984 and is a senior consultant to the Bush campaign.

Though the emphasis was on revving up the committed, the campaign also took advantage of the proximity of New Hampshire to woo business leaders, law enforcement officers and members of the news media from the first primary state. A delegation from the first caucus state, Iowa, was due in today. Over a week's time, at least 200 people, in about two groups a day, were ushered in and out of the Bush compound.

Even though the seductive attractions of Kennebunkport are unlikely to have much of an impact on the GOP nomination fight, Bush staffers were reveling in whatever advantage they wanted to believe it gave them this week. "What's {Kansas Sen.} Bob Dole going to do?" mused one Bush operative. "Rent a trailer and invite all the New Hampshire police chiefs down to see him in his Airstream?"