If God had meant for us to ride around on Indian summer days in a closed sedan with air conditioning, he would have put wheels on our caves. Surely Mother Nature had something else in mind when she allowed somebody to invent the internal combustion engine: namely, sports cars.

Even the earliest car makers had the good sense to build only convertibles or cars with no tops at all. Zipping along with wildflowers at your side, God's own air conditioning for climate-control and the whole sky for a roof is getting back to nature while getting from here to there.

Washington is a good sports-car town. Compared to Atlanta, Miami and Los Angeles, of course, our town loses a few points due to winter snows and the daily summertime smogfest at 16th and K. But in contrast to Chigaco or New York, Washington is a roadster's heaven. To take advantage of this, pop the top on your four-wheeler in the morning and devise a drive to work that takes you around the Lincoln Memorial, alongside West Potomac Park and through the Mall. Or in the evening, sweep along George Washington Parkway and loop under Arlington Memorial Bridge so that you can create breathtaking views of the highlighted Lincoln Memorial and Kennedy Center, framed by bridge arches-a scene that always reminds me of Paris.

The other singular joy of roadstering in the mid-atlantic region lies in Washington's propitious locale between mountains and sea. For scenery and joys of tight-turn driving, it's the mountains, hands down. Or hands up, on the wheel. Except for a distressing overabundance of other motorists with the same idea, an almost-perfect roadster's jaunt is the trek out Route 50 through Middleburg and Upperville towards the northernmost tip of the Skyline Drive at Front Royal, Virginia.

Middleburg, flanked on either side by the undulating horse farms and overpriced antique dealers that make Virginia famous, is an excellent first stop during a weekend run to the mountains. Despite a patina of tourist trappings, the town remains a well-preserved community for the fox-hunting set. Two resurrected inns, the Red Fox Tavern and L'Auberge, have become a favorite Saturday even and Sunday lunch destination for Washingtonians. After a drink or a meal, stroll up one side of main street and down the other.

The scenery becomes more stunning, especially in an open car, on the nine-mile stretch from Middleburg to Upperville, an even smaller gem of gentry living. Split-rail fences give way to long stretches of white-plank enclosures and horse-jumping facilities. And on a hilly highway whose serpentine path has changed little since it was first used by post coaches and by the armies of Lee and Jackson, the sports-car driver is able to put his latter-day carriage through its paces. If you can go on a weekday or when traffic is light, the road is a driver's delight.

Route 50 does not lead directly to Skyline Drive, so you can take any of the well-paved secondary roads lacing Fauquier and Rappahannock Counties to reach one of the national park's entrances. The landscape is dotted with a more modest variety of prosperous-looking farms, rough-cut fieldstone houses and creeks that drain the mountainous watershed. The true joy of roadster-riding is that you see, feel and smell every change of nature as you move along.

The air begins to lighten as your altitude rises and it may be time to break out a windbreaker or a wooly by the time you are paying the $2 entry fee to the park. We found heavy sweaters with high necks the perfect topless traveling gear in the chilly 3,500-foot Blue Ridge. A golf- style cap and driving gloves also felt good at these temperatures. Remember, the aerodynamics of roadsters brings in the cold air from behind you.

There are five campgrounds and three lodge facilities on the twisting two-lane, 105-mile Skyline Drive. The availability of accommodations for that day is posted at each entrance to the parkway. We went at a time when the lodges were filled and it was too cold for comfortable camping, so we decided instead to investigate the spectacular views of the Shenandoah Valley. One can drop off the drive down into the valleys on either side at about 35 miles.

This part of Virginia is well provided with commercial camping areas, low-priced old motels and even a few restored country inns, such as the Sky Chalet near Mount Jackson. But the greatest fun in the sporster is simply cutting out across weaving secondary roads (all with numbers in the 600s) and letting the car follow its nose to a creekside picnic site, to a dead-end deep up a mountain hollow or to a crossroads village with a white-steepled church and an unregenerate general store. Even the names on the country mail boxes become a source of migratory fascination. The extraordinary number of Shipletts residing on both sides of the Blue Ridge between Welkton and Standardsville conjured visions of Scottish Irish settlers hacking their way through Swift Run Grap nearly 200 years ago.

Sports-car driving is like sailing: Getting there is more than half the fun. Also like sailing, the roads turn you this way and that so the car becomes a rolling sunbath. Logging over 200 miles in a short weekend (well, we had just bought the thing), our route easily embraced Charlottesville, where an off-season visit to the classic Rotunda at the University of Virginia-perhaps Jefferson's crowning architectural inspiration-is a calming and uplifting experience. It makes the oversold hurly-burly of Williamsburg look like Disneyland. All these were places we intended to visit someday, but thanks to the car with nothing on the top, it finally happened.