PARK CITY, Utah — It was the kind of image Mitt Romney has sought to blunt during his campaign for president: a prodigious display of wealth.

At a private retreat this weekend, major Romney campaign donors quaffed 1927 Port they'd brought in for the occasion, mingled in the lobby of a posh resort called the Chateaux at Silver Lake and watched an aerial display of Olympic ski jumpers.

Billed as a "senior leadership retreat," the three-day gathering in Deer Valley was a reward for the wealthy GOP donors who have fueled Romney's fundraising, giving at least $25,000 each or raising at least $100,000 by June 18. Many of the more than 700 who attended had donated much more.

The campaign is counting on these supporters to raise $500 million of its $800 million fundraising goal, according to one top fundraiser. The retreat is part of a meticulous effort by the campaign to keep its biggest supporters personally invested in the candidate as he hurtles toward November.

"They're our major investors," a senior Romney adviser said, declining to speak openly because of the campaign's desire for secrecy.

Romney surrogate John Sununu, the former New Hampshire governor, said the event was meant to cater to donors who "appreciate being kept in the process after they've written the check."

Sununu was among the speakers on the opening day of festivities Friday, which was capped by a cookout at Olympic Park. Donors dined on barbecue and salmon under a tent overlooking the site of the 2002 Winter Games' ski jumping contest, and were treated to an exhibition of synchronized skiers careening down steep ramps and doing flips in the air before landing in a pool. Romney, the donors did not need to be told, led the Utah Games.

Later, donors gathered at the lobby bar of the Chateaux, the stone ski lodge where many of the events took place. Romney's top advisers — including his rarely seen campaign manager, Matt Rhoades, huddled at a table in one corner while donors sipped cocktails at the copper-topped bar.

South Dakota Sen. John Thune, one of several potential vice presidential picks attending, mingled near Beth Myers, a longtime Romney confidante who is leading the search for the running mate. He demurred when asked about the possibility of landing on the ticket.

The retreat was closed to the media, in keeping with Romney's secrecy about who is raising money for his campaign. He has declined to release the names of bundlers, those who collect funds from others on behalf of the campaign. Romney was not seen in public except when he waved at reporters from his motorcade.

It was a busy weekend for top conservative donors. In addition to Romney's retreat, the billionaire Koch brothers were hosting a private gathering in Carlsbad for wealthy political givers. And the Republican Jewish Coalition — whose board includes casino magnate Sheldon Adelson and other top GOP money men — is having its summer bash at a Beverly Hills hotel Sunday.

Donor getaways have increasingly become the norm in presidential fundraising, as campaigns take cues from similar retreats in the corporate and academic worlds.

Donors described hearing repeatedly from Romney and his wife, Ann, who hosted a women's tea Saturday. Top Republicans, including Sen. John McCain, former Florida Gov. Jeb Bush, former Secretary of State Condoleezza Rice, Louisiana Gov. Bobby Jindal and Rep. Paul D. Ryan of Wisconsin also addressed the group. Rice's speech on Saturday got rave reviews.

Donors chose from policy panels on matters such as Israel, health care and the financial industry headlined by prominent Republicans such as Hewlett-Packard chief and failed California gubernatorial candidate Meg Whitman and strategist Karl Rove.

Rove helped found American Crossroads, a super PAC that cannot coordinate its message strategy with Romney's campaign but can collaborate on fundraising. Its sister nonprofit, Crossroads GPS, has already spent millions assailing President Barack Obama's record.

Speakers were chauffeured to events in golf carts, as a Democrat charged with tracking their activities watched from the side of the road. A corporate jet registered in the care of Bain Capital, the private equity firm Romney once headed, was spotted at a nearby private airport.

The weekend was to wrap up Sunday, one donor said, with a round of golf at Red Ledges, a private Jack Nicklaus-designed golf course that was named the best new course in the country in 2009.