Bill Hutchinson has hiked in nine countries, but one of his favorite trails is a little-known footpath in Fairfax County only 20 miles from downtown Washington.

Hutchinson, a retired historian and past president of the Potomac Appalachian Trail Club, goes out every week to any one of about a hundred foot trails near Washington. Most are little-used, apparently unknown to the many hikers who converge every weekend on the big-name Appalachian Trail and other popular footpaths.

"I've been to the high Alps of Austria and the tundra of Norway, and I've looked the glaciers right in the eye," Hutchinson says, "but you can put me down on a trail anywhere around Washington and I can enjoy a hike. It doesn't have to be one of the well-known trails."

The path in Fairfax County meanders through a forested stream valley and climbs to high bluffs overlooking Bull Run and Occoquan Lake. Blazed just a year ago, the trail starts at HEMLOCK OVERLOOK PARK at the end of Yates Ford Road (Virginia Route 615) near Clifton and goes about eight miles south and east to Fountainhead Park, passing through part of a 5,000-acre regional park preserve. To shuttle back, park a second car at the Fountainhead Visitor Center on Route 727. "It's a good walk," Hutchinson says, "an interesting area, and a lot of good climbs up over the bluffs." Another of Hutchinson's favorite hikes off the beaten path is the southern part of the new Catoctin Trail in the wilds of the Maryland mountains. Go to GAMBRILL STATE PARK off U.S. 40 just west of Frederick. Stop at the first parking area and follow the blue blazed trail through dense mountain laurel and a hardwood forest mixed with pines. Keep an eye out for deer and turkeys. "That's quite a pleasant trail," Hutchinson says. "After a few miles, it drops into a nice hollow (Clifford Hollow) and switches back and forth, down and up, really a nice layout. Most people don't realize there's anything like that so close to home." If you're looking for easy strolling in scenic woods, Hutchinson recommends several little-known trails in PRINCE WILLIAM FOREST PARK in Virginia's Quantico Creek Valley, about 30 miles south of Washington, off I-95. There the beautiful Piedmont country begins and the National Park Service and PATC maintain circuit trails along the streams and ridges and some that pass near small secluded lakes. Stop at the park headquarters and pick up a free trail map. Explore on your own to find the less-used trails, or ask a park ranger about the getaway places in the rolling 17,000-acre forest. Hutchinson's favorite trails go out from the nature center. "It's about 10 miles of pleasant walking," he says. He takes a trail (No. 10, orange blazed) down to a stream and up over some hills, passing through pine forests and old farmsteads now buried in time. He comes to a white-blazed trail (No. 8) at the South Fork of the Quantico and follows this upstream to the Oak Ridge camping area. From there, he follows an old farms-to-forest nature trail to a pristine beaver pond near the North Fork, then makes his way through the woods downstream until he picks up some blue-blazed trails, which he follows back to where he started. Don't try it without a map. "There's a little bushwhacking, but it's civilized bushwhacking," Hutchinson says. He doesn't spend all of his spare time hiking. He also maintains a section of the Applachian Trail near Ivy Creek in the south district of Shenandoah National Park and the less-known RIPRAP TRAIL on the west side of Skyline Drive. "That's my real favorite -- the Riprap," he says. "If you're willing to get out a bit in the rugged areas, that's one of the nicest walks in the park, 10 stimulating miles." The footpath winds along a high ridge, climbs around the upthrust Calvary Rocks, then drops into the deep cold Spring and Riprap Hollows, where rhododendron thrive. Hutchinson climbs out on the Wildcat Ridge Trail, then follows the Appalachian trail winding through the mountains back to the Calvary Rocks parking area. There aren't many people in this wild south section of Shenandoah Park, and Riprap is unknown to the tourists who throng to Big Meadows and Front Royal. You may meet a slender graying man in khaki swinging a brush cutter. That will be Bill Hutchinson, a twinkle of pride in his eyes because you're walking his trail -- the Riprap. TRAILING OFF INTO. . . For information about other little-used trails near Washington, send away for copies of "Hikes in the Washington Area," Books A and B, from the Potomac Appalachian Trail Club, 1718 N Street NW, Washington 20036; $7 for both books plus $1 for postage and handling. Or join PATC's Wednesday hikes and weekend excursions. Call 638-5306 for information..