Autumn is a time of high color in the Colorado Rockies. A season when the peaks of the San Juan Range, the Elk and Ragged Mountains are splashed with red and yellow hues.

Almost anywhere you go in Colorado you'll find a symphony of color from mid-September through the first week of October.For a celebration of autumn, however, you must travel to the southwestern corner of the state where 12 towns have declared a "Colorado Colorfest" in the San Juan Mountains - among them, Pagosa Springs, Ouray, Telluride, Cortez and Durango, where the festivities originated 10 years ago.

Colorfest seems to offer something for everyone: hot air balloon and hang glider rallies, art and film festivals, Indian powwows, bicycle tours and races, foot races, a culinary arts festival, canoe and kayak races.

The San Juan Range is rich in history as well as imposing scenic beauty. Before the coming of the white man, these mountains were the haunt of the Ute Indians. Spanish explorers named them, and in the late 19th century they were swarmed over by miners and prospectors in search of gold and silver.

Three peaks - Sneffels, Uncompahgre, (Ute for red water spring), and Whetterhorn - are over 14,000 feet, with countless lesser peaks enfolding glaciated basins and small sparkling lakes.

The area's highest passes, Molas and Red Mountain, are above 10,000 feet, whereby U.S. 550 threads its way 43 miles between Durango and Ouray.

The last 23 miles of this road, north of the historic mining town of Silverton, is the so-called Million Dollar Highway, built according to legend with gold- and silver-laced tailings.

It is this daunting route that challenges cyclists the third week in September during a three-day tour of the San Juans, with overnight stops at the resort towns of Ouray and Telluride.

For the fat-tire devotee, there is the Pagosa Springs Mountain Bike Race, or the Telluride Mountain Bike Classic. Both events are held in mid-September, as is Telluride's Hang Gliding Festival whereby onlookers thrill to aerial acrobatics. Silverton hosts the Deer Park Hill Climb, a mountain run of 3,000 vertical feet over four miles.

Less exhausting: Durango's Western Arts and Film Festival, held the second week in October.

While Colorfest is a nice touch, you needn't structure your tour around it. The splash of autumn color across the San Juan Range can be reward enough.

An option for those with time to spare is a 175-mile loop drive, angling north from Durango by way of Silverton, Ouray and Ridgway, thence west across the Dallas Divide (with sweeping views of the San Juan Mountains) to the junction with State 145 at Placerville.

Turning south at Placerville on Colorado 145, you follow the San Miguel River to Telluride, crossing Lizard Head Pass at 10,122 feet. Beyond the pass the highway makes its descent through strands of spruce and aspen to the canyon of the Delores River. Return to Durango by way of Delores and Mancos.

It is much the same route followed by the old Rio Grande Southern narrow gauge railroad. Remnants of the roadbed are yet visible along precipitous mountains and in the depths of forbidding canyons.

From 1931-50 the Galloping Goose, half-train, half-car, plied this line, hauling both passengers and freight. The ride over Lizard Head Pass was described by one passenger as akin to going over Niagara Falls in a barrel. One of these hybrid contraptions can be seen in Telluride, another at Delores.

The loop can be driven in a day, although two, or even three days are best, for there is plenty to see and do.

Back country jeeping on old mining roads, hiking, backpacking, mountain biking, fishing, camping in the national forests, are among the options. The resorts offer ballooning, horseback riding, chairlift rides, and for those so inclined, there are a plethora of shops and galleries in which to browse.

For many, a ride on the Durango and Silverton narrow gauge line is the high point of a San Juan Mountain tour. Two trains are scheduled through Sept. 30 and one train through the end of November, departing daily from Durango.

In the autumn, the 45-mile, four-hour ride through the impressive gorge of the Animas River is enhanced by nature's palette of colors. During the busy autumn months the trains disgorge upwards of 1,000 passengers daily in Silverton.

With only two hours to spend, most engage in a frantic souvenir hunting spree, or head for the nearest restaurant. Silverton is best savored after the trains leave, although at night the town has a reputation for rolling up its boardwalks.

A better choice for overnight lodging is Ouray, the self-styled Switzerland of America and famous for its mineral baths, or Telluride, a one-time mining camp turned ski resort, where there is rarely a dull moment. Saturday night at the Fly Me to the Moon Saloon - the place really jumps. Good eating and first-rate accommodations in both towns. Reservations are a must.

For details concerning these and other events, contact the Durango Chamber Resort Association, Box 2587, Durango, Colorado, 81301. (303) 247-0312.