When most families go on a summer vacation, they don’t have a political-action committee to pay the bills.

Not so for Sarah Palin, the former vice presidential candidate and Alaska governor, who has joined her husband, children and parents in a widely publicized bus tour of East Coast historic sites this week.

The trip appears to be part vacation, part political rally and part reality show. Fuel, lodging and other expenses are being paid for by SarahPAC, Palin’s political committee, which is also soliciting donations online in connection with the journey.

“You can show your support for the Fundamental Restoration of America and the ‘One Nation Tour’ by making a generous donation to SarahPAC today,” reads a message on the SarahPAC Web site.

The arrangement is perfectly legal, campaign-finance experts say. SarahPAC is set up as an unconnected PAC, meaning that the usual restrictions on candidate committees don’t apply. Regular candidate committees, for example, are barred from converting campaign money to personal use.

As a result, unless Palin decides to formally explore a possible presidential run, she is free to spend the money raised by SarahPAC for “any lawful purpose” under federal law, experts said. That means it doesn’t matter whether the trip is a holiday, a political event or something in between.

“Not only can she use SarahPAC for a family vacation, she could use it for her home mortgage payments or anything else she wants,” said Paul S. Ryan, associate legal counsel at the Campaign Legal Center, an advocacy group focused on election laws.

Traveling in a brightly decorated bus — which is labeled “Paid for by SARAHPAC” — Palin kicked off the “One Nation Tour” Sunday with an appearance at the Rolling Thunder motorcycle rally on the Mall. Stops since then have included Mount Vernon in Virginia, the Gettysburg Civil War battlefield in Pennsylvania and the Statue of Liberty in New York Harbor.

Reporters are being kept at bay throughout much of the trip, with even lodging details kept secret.

Timothy Crawford, treasurer of SarahPAC, said all expenses and contributions connected with the tour will be disclosed next month as part of the committee’s regular report to the Federal Election Commission.

When asked how much the trip will cost, Crawford said: “I hope not as much as we’re raising. The fundraising is going very well.”

Crawford said the tour will abide by all applicable campaign-finance rules. “It’s a SarahPAC tour, and SarahPAC is raising money to pay for it,” Crawford said. “It’s really very simple and straightforward.”

Launched in 2009 after Palin’s failed bid as the vice presidential pick of Sen. John McCain (R-Ariz.), SarahPAC raised nearly $5.7 million during the 2010 election cycle and had about $1.3 million on hand at the end of last year, according to FEC data compiled by the Center for Responsive Politics.

Most of the PAC’s expenditures were for consultants, fundraising, travel and other internal costs; SarahPAC also gave about $570,000 to various Republican candidates around the country in the last cycle, records show.

Fred Wertheimer, a longtime campaign-finance activist who heads the Democracy 21 advocacy group, said the Palin tour illustrates the broad leeway given to potential candidates as long as they don’t formally declare their intent to explore a presidential campaign. Once they do, they must form a new committee that adheres to regular contribution and expenditure limits.

“If Gov. Palin is treating this as a family vacation, then she ought to be paying for it with family funds,” Wertheimer said. “But if this is a prelude to announcing her presidential campaign, then she ought to have a presidential exploratory committee.”

Wertheimer also noted that if the tour is treated solely as a vacation, the Palins could owe income taxes on the payments from her PAC.

“Most casual observers would probably believe that Sarah Palin is, at the very least, testing the waters for a presidential run,” said Ryan, from the Campaign Legal Center. “But not only is she not a candidate, she is seemingly denying that she’s even testing the waters.”

Palin herself bristled at questions Wednesday about how the tour was being funded. She said during a visit to the Statue of Liberty that the bus was “our own personal motor home” and that SarahPAC was paying for the trip.

“Check SarahPAC.com,” Palin told ABC News. “I don’t know why in the world you would ask a question like that. I’m just thinking about America and our foundations and our freedoms and our opportunities.”

She added a moment later: “I’m not asking you to pay for a penny of this trip.”