Harold Phillips is a 72-year-old retired chicken farmer from Winchester, Va., and when he gets the chance, there's one place on earth he likes to be: breezing along the winding highways in his 32-foot motor home.

His recreational vehicle has a microwave oven, a color television and a brown-upholstered dinette that unfolds into a bed. It drinks a gallon of gas every six or seven miles, but the way Phillips figures it, "if you've got to worry about the price of gasoline, you don't buy the unit."

The availability of gasoline, rather than its price, is typically the most important concern of motor-home owners, industry experts say. But some people believe plummeting gasoline prices, combined with lowered interest rates and a fear of traveling abroad, will spark a surge in first-time RV buyers and renters.

Another factor favoring the business is the coming of age of baby boomers, because studies show that most RV owners begin buying at age 35. They've already purchased a house, have the income to afford the minimum $20,000 for an RV, and are searching for family-oriented vacation options.

"Everybody is just as optimistic as anything," said Christine Morrison, spokeswoman for the Recreation Vehicle Industry Association, which is based in Reston and represents 570 RV suppliers and manufacturers. "Everybody is very confident that this is going to be a great year."

The $8 billion-a-year RV industry hasn't had a boom since the early '70s, observers say. Last year was especially poor, with overstocked lots, despite a 9.8 percent drop over the previous year in the shipment of new models to dealers, said RVIA's Morrison. So, the gasoline price drop, combined with the other factors, is welcome news.

Morrison was unable to predict sales for this summer, but said the economic indicators are perfectly aligned. "We really haven't seen a change in the number of shipments yet, but I can tell you that everybody in the industry expects this is going to be a real turning point."

The forecast is a little more cautions at Indiana Business Research Center at Indiana University, where researchers predict an 8.85 percent jump in RV shipments this year, from 362,430 in 1985 to 394,520 in 1986 -- followed by a 5.9 percent drop next year.

The center warns of a possible gasoline tax in the third quarter of this year, which could affect pump prices and RV sales. Researchers there also wonder about intangibles, such as baby-boomer attitudes toward RVs. "Do they have the kind of desire to buy it?" asked Leslie Schenk, a research associate.

Other studies show a "one-to-one correlation" between a change in the real price of gasoline and RV sales, said David Tarrant, who manages RV sales for Ford Motor Co., a major producer of RV chassis.

"If, in the first quarter this year, gasoline went down 10 percent, you can be sure that in the second quarter, RV shipments will be up 10 percent," he said.

Locally, sales personnel at RV centers say business is good for a variety of reasons, including pent-up demand. Special auto-financing plans encouraged many people to buy cars and trucks in 1985; as a result, they postponed a contemplated RV purchase until this year or later.

A Ford Motor Co. study indicates that more than 25 percent of American households have a very strong interest in owning or operating an RV. According to research done by the University of Michigan, 6.2 percent of all U.S. families have expressed interest in buying a new RV, and 19 percent of non-RV owners would consider renting an RV.

In Fairfax City, Lindsey Reines of Reines RV Center hasn't noticed much change because of falling fuel prices. "I think it helps, but I don't have anybody coming in here now and saying, 'Gas is 80 cents a gallon; I'm going to buy an RV.' "

At Safford RV in Laurel, manager Vince Martin reported a 30 percent increase in traffic over last year. "Interest rates and gas are two important things, but gas is number one," he said.

In Vienna, Norma Penny of Penny Motors Inc. said business is up 10 percent. "A lot of them are coming in with the statement that they're going to buy because of the gas," she said.

Customers there also are expressing more than the usual amount of interest in the large models, including the $60,000 Xplorer 370, which features a built-in color television, an "inviting conversation center" and a custom-designed galley.

Many RV owners concede that lower gasoline prices won't affect their travel plans, but they like what they see at the pumps.

"I'll use approximately 30 gallons of gas a day when we're moving," said RV owner Woody Barron, a 67-year-old retired Alexandria building inspector. "So, you're talking about a 20-cent difference. So, you're talking about six bucks a day. We don't travel on Sundays, so that's about $36 a week."

Some, like Homer Cook Sr., of Perryville, Md., near Baltimore, believe gasoline prices will make a difference in where they go. "Like I say, we're on retirement. You only have so much money, and you have to stretch it as far as you can stretch it," said Cook, who owns a 35-foot Kountry Aire motor home.

Gasoline prices also may be responsible for the sudden explosion of interest in the Good Sam Club, which is based in California and describes itself as the nation's largest RV owners' association, with 470,000 members, said Sue Bray, the executive director.

Memberships aren't up dramatically, but participation is. Everything Good Sam had planned for this summer is nearly sold out, including the August rally of 1,600 RVs in Springfield, Ohio.

Three times the usual number of RVers also are requesting help from Good Sam's custom trip-routing service, and they're booking longer trips -- to places such as Alaska, Texas and Florida.

"I think the overall idea is that people are seeing that the gas prices are down," said Bray. "They don't know how long they're going to be down for, and they want to take advantage of them and travel."