THE IMAGE is from a bygone era: A summer countryscape of rolling pastures and distant farmhouses, the afternoon quiet broken by a laughing group of friends bobbing down the river aboard a makeshift fleet of inner tubes.

Not far from Charlottesville, those days are very much alive again.

Tubing may be an old-fashioned pastime, but it has become very popular with adults as well as youngsters on many rivers across the country. In central Virginia, enthusiasts head for a three-mile stretch of the swift-flowing, but basically gentle James River.

For visitors to Thomas Jefferson country and Charlotteville's other historic sights, a sunny afternoon on the James can be a refreshing break. The people at James River Runners Inc., on the bank of the James at Hatton Ferry, make it fairly simple to take the plunge.

Now in its fourth year, the canoe livery will rent you a tube and shuttle you upstream three miles, at a cost of $5.50 per person. You float back down on your own to the livery dock and your waiting car--a trip of two to five hours, depending on how lazy a pace you want to keep.

For another $3.50, the livery will rig up an additional tube to hold your picnic cooler, and it tags along at the end of a rope until you haul it in for a soda or a sandwich.

The livery is open daily in the summer, and the upriver tube shuttles run from about noon to 3:30 p.m. About 125 tubes are available for rent, and they can sell out on a busy weekend, so reservations are necessary. Hatton's Ferry, site of the last hand-poled ferry in the United States, is about 35 minutes southeast of Charlottesville on Route 625 near Scottsville.

"It's pretty much a gentle float trip," says livery owner Jeff Schmick, 31, who grew up canoeing in the region. The last 100 yards are easily negotiable Class I and II rapids, which many of his customers bounce through repeatedly before turning in their tubes at day's end.

In midsummer, the James is only about two to three feet deep, says Schmick, which he feels makes it reasonably safe for youngsters as well as adults.

The river flows through mostly farm country, edging around many small islands, which make fine spots for picnicking though it is necessary to watch out for poison ivy. The water is quite clear, which Schmick says makes it easy to spot blue gills, bass and other fish swimming under your feet. Wiggle your toes, and maybe you will get a nibble.

For information and reservations: James River Runners, Route 1, Box 106, Scottsville, Va. (804) 286-2338.

TOURING TOGO: This tiny West African nation, once a colony of France, is making a bid for North American tourists, whom it feels are unaware of the nation's fine hotels and beaches that have made it a popular holiday destination for Europeans. It has dropped visa requirements for U.S. and Canadian citizens and opened an information service in Washington.

Beyond the beaches, the politically stable, French-speaking nation of 2 million people considers itself a "microcosm" of Africa, incorporating within its narrow boundries many aspects of the continent: coastal lowlands, lush forested mountains and the more-arid high plateaus, where visitors on a photo safari might spot lions, panthers, elephants and other wildlife.

Lome, the capital, is a bustling city with a colorful market. The bright, batik fabrics are eye-pleasing, and nearby is the fetish market, selling magic charms and potions.

Several travel firms offer tour packages to Togo or include it in an African itinerary. Air Afrique is currently quoting a $720 fare from New York City.

For information: Togo Information Service, 1625 K St. NW, Washington, D.C. 20006, 659-4330.

REDCOATS IN MARYLAND: An often overlooked battle in early American history is the British invasion of Maryland in 1814. In August of that year, a large British fleet and 4,000 troops attempted to end the War of 1812 in a stroke, landing in the village of Benedict on the Patuvent River.

On June 26, the Smithsonian Resident Associates program is offering a day-long narrated bus tour tracing the invasion route and visiting the scene of major actions in southern Maryland. The fee is $40 for members; $48 for non-members.

For information: 357-3030.