THREE WEEKS after its official arrival, the advance guard of autumn has invaded the Washington area, tinting the tips of elms, maples and oaks with a hint of the invading army of color poised in the north.

Splashes of golds, reds and yellows can be seen in trees inside the Beltway, and farther away, in the upland forests of West Virginia, western Maryland and Virginia, the annual change from green to glory is well underway.

This weekend and next, the trees of those highlands will be in full color. The trees of Washington and its suburbs will turn fully later, around the last week of October, with the forests of central and Tidewater Virginia fighting off the metamorphosis until November.

With this explosion of color comes the season of country drives, long walks and harvest festivals. Within this region are a number of roads and parks offering some stunning views of the foliage and festivals to celebrate the time of year.

Almost any road that leads away from the Beltway will in time turn into a lane lined with spectacolor, but perhaps the most popular fall drive in the region is Skyline Drive, the mountaintop road in the Shenandoah National Park.

The 105-mile Skyline Drive is in autumn what the Woodrow Wilson Bridge is in rush hour. An estimated 100,000 visitors will crowd the drive, facilities and campgrounds in the park this weekend and next, creating a traffic jam and otherwise spoiling what could be a beautiful experience.

There are two ways, though, to beat the rush. Go in the middle of the week, when traffic is not impossible, or drive south on U.S. 29 to Charlottesville, Va., (in itself a wonderful drive), turn west on U.S. 250 to Rockfish Gap, and take Skyline Drive north. You'll be going against the traffic, since most foliage voyeurs on the drive head south from Front Royal (which holds a Festival of Leaves at Chester and Main streets 9 to 5 Saturday and noon to 5 Sunday; call 703/636-1446). Either way, it will cost you $5 per car to enter the park.

A better option, if you have the time, would be to skip Skyline Drive, drive down to Rockfish Gap on U.S. 250 and take the 469-mile Blue Ridge Parkway south to Asheville, N.C. This drive is, in my opinion, much more scenic than Skyline Drive. There is half the traffic during the fall foliage season, the views are even more beautiful, and the mountains are twice as high (Mount Mitchell north of Asheville is more than 6,000 feet high). The higher elevations mean the trees throughout the length of the parkway will be at their peak sometime between Monday and the end of the month. Admission to the parkway is free.

Not all of us have time for an overnight trip, so for a one-day tour of the countryside, try driving Route 7 west from the Beltway to Winchester, Va., and back. You can expand this trip by taking U.S. 11 south from Winchester through the Shenandoah Valley to either Strasburg, Va. (and Route 55 east and back), or New Market, Va. (and Route 211 east to U.S. 29 and I-66 east and back).

Route 50 west from the Beltway offers not only some fine views of autumn colors, but the joys of browsing through the shops in Middleburg, the capital of Loudoun County's horse country, and a Harvest Festival on Oct. 20 in tiny Aldie, Va. The festival is from 10 to 5 at Aldie Mills in the hamlet. Attractions include artisans, Civil War reenactments, food and music. Admission is free.

I-95 south from Washington to Richmond passes through some mighty forests, but the traffic is a killer. Try U.S. 1 south from Woodbridge to Fredericksburg, Va., a colonial city always worth visiting, and then return via U.S. 17 west to Warrenton, Va., and U.S. 29 north to I-66 east to the District.

In Maryland, my favorite drives include I-270 north to Frederick and then U.S. 15 north to Gettysburg, the National Battlefield Park in Pennsylvania. Along the way you will pass Cunningham Falls State Park and Catoctin Mountain Park. U.S. 15 will be popular this weekend, because the Catoctin Colorfest, a huge craft festival that draws an estimated 350 artisans and 100,000 visitors, will be held from 10 to 6 Saturday and Sunday in Thurmont, on the edge of Catoctin Mountain Park (call 301/271-4432). The festival is free, and is in two parks next to the Cozy Restaurant, an establishment well-marked by numerous billboards. You can't miss it. The park joins in the fun with nature hikes and seminars.

A bit closer to Washington is Sugarloaf Mountain. Take I-270 north to the Comus exit and follow Route 95 past Comus and to the park entrance. The outlooks at the summit offer striking views of the foliage and the Maryland countryside.

If festivals are more to your taste than foliage, try the fine fall festival this weekend in Westminster, on Route 27 in Maryland's wine country about equidistant from Frederick and Baltimore. Fall Harvest Days at the Carroll County Farm Museum, at 500 S. Center St., features hayrides, scarecrow-making, country foods and crafts and entertainment from 10 to 5 Saturday and Sunday. Admission is $4, $1.50 seniors and children 6 through 18, free for those five and younger (call 301/848-7775).

Another drive better done as a weekend trip is into western Maryland. Take I-70 west of Frederick to U.S. 40 west. This road, once the first highway west to the frontier outpost called Chicago, passes over some steep mountains before going through Hagerstown and continuing west to Cumberland and Garrett County. Along the way it passes Gambrill State Park (two miles west of the U.S. 40 exit from I-70), Greenbrier State Park (where U.S. 40 crosses I-70 again), and Green Ridge State Forest (18 miles west of Hancock). All these parks are filled with exceptional autumn foliage.

Even farther west, just before the Maryland border, Route 219 turns south from U.S. 40 to Deep Creek Lake and nearby Oakland, Md., site of the Autumn Glory Festival, Friday through Sunday. The festival goes on through the day and evening and features bagpipe concerts, fiddle contests, parades, arts and crafts, local foods and other entertainment. The festivities are held in downtown Oakland. There are separate admission fees for each event, but nothing more expensive than $5. Call 301/334-1948.

On Maryland's Eastern Shore, there are two lovely drives to the colonial port cities of Chestertown (U.S. 50 east across the Bay Bridge to U.S. 301 and Route 213 north) and St. Michaels (U.S. 50 to Routes 332 and 33). The trees are lovely along the way, and the two cities are full of historic buildings and interesting shops. Adding to the moment are the wintering flocks of Canada and snow geese, ducks and swans, visible on coves in Miles River and in farm fields.

Another recommended destination, if you go this weekend while the colors are full, is Pennsylvania's Brandywine Valley. Take I-95 north to Wilmington, Del., then Route 52 north into Pennsylvania and such attractions as Winterthur, a massive mansion filled with antiques and decorative arts; the Longwood Gardens, the du Ponts' version of the gardens at Versailles; and the Brandywine River Museum, which displays works of three generations of Wyeths.

Finally, for those who prefer to see while moving at a slower pace, Rock Creek Park from Montgomery County to the Potomac and the towpath along the C&O Canal offer fields of beauty.