For Laurie Potter, the breaking point came last week when she drove into Napa and found diesel selling for $5.25 a gallon. Her commitment to the RV lifestyle crumbled.

Some people might be able to swallow paying $450 to fill a pickup, but she’s not one of them, said Potter, who had been riding in a Dodge Ram pulling a trailer

Now she’s selling both. “There is a threshold for anything you do,” she said. “It’s not worth it to me anymore.” In the future, she and her husband will stay in motels when they travel.

Parked on her pad at the Napa Valley Exposition RV park was a new Nissan Versa, an economy car purchased the day before on Soscol Avenue.

Her Ram got 10 mpg pulling the trailer.

With the Versa “they said 38 on the highway,” she said.

Skyrocketing gas and diesel prices are hitting every motorist in the pocketbook, but none more so than RV owners. Some of the biggest homes on wheels burn a gallon every seven miles.

Campers at the Expo’s RV park told stories last week of cutting back on their travel itineraries and other economy moves as fuel prices climb into uncharted territory.

Rod Hurley, a retired Napa garage owner, would normally stay in the Napa area until late summer, then sightsee across the U.S. before wintering in Arizona.

With gas costing a fortune, Hurley said he

wouldn’t do an East Coast trip this year. “I can’t afford to,” he said.

Hurley was camping next to George Bradley, a retired Napa firefighter, and his wife Marilyn. They had been on the road two months since leaving their new home in Montana.

George estimated they had spent $1,200 in diesel fuel traveling through western states. His wife, who had logged every purchase, said $1,500 was more like it.

When they left Montana on March 22, they paid $4.03 for diesel. Last Monday in California they paid $4.99, which is now looking like a bargain, she said.

To save money on fuel, they only went as far as Arizona, eliminating a swing through New Mexico, said George. He gets 10 to 12 mpg pulling a fifth-wheel trailer.

The Bradleys said they might have to reexamine their commitment to RVing depending on what fuel prices do in coming years. “We have a goal in life to enjoy life, but we may eventually change our plans,” George said. In the meantime, “let’s do as much traveling as we can.”

The Expo’s RV park is watched over by campground hosts Kenny Beck and Dave Sather who rotate duty. RV owners are staying longer as a way of conserving on fuel, Beck said.

“It rips your insides right out” to pay $5 for a gallon of diesel, Beck said.

Because many RV owners are affluent, high prices may not quash their desire for traveling with all the comforts of home, Sather said. “You don’t spend $500,000 on a motor home if you’re worried about $5 fuel,” he said.

As a retired public works employee, Sather said he didn’t have an unlimited budget, which is why he volunteers for camp host, receiving free camping in exchange. The Expo charges $35 a night, with $4 discounts for Good Club Sam members.

Sather said he paid $254,000 for his motor home, which gets a “solid 7” mpg on the highway. To his dismay, he recently paid $692 for diesel and propane.

“I don’t like to pay it, but I didn’t buy it to park it either,” he said.

Living in an RV does have its economies, Sather said. What other tourist can spend $62 for two nights’ stay in the Napa Valley?

Carolynn Roberts, a retired county employee from Santa Clara, said she sold her home in June 2006 and has been living in her 38-foot RV ever since.

She put 4,000 miles on her RV last year, but will travel less this year. She will economize by staying longer at RV parks and using her 21-mpg car for day jaunts.

Roberts has no plans to go back to a rooted existence. “This is the dream I’ve had since I was a little girl,” she said.

Come 2009, Roberts plans to drive to the East Coast and see the sights for a year or two. She will travel with her four cats.

Without her 38-foot, 7-mpg RV, such a trip just would not be possible, Roberts said.