You can drive your Audi to Aspen. You can ride your Volvo to Vail. But if your destination is Steamboat Springs, Colo., an equally spectacular skiers' mecca, the appropriate vehicle would probably be that workhorse of the mountain west, the plain old pickup truck.

Steamboat Springs, an alpine extravaganza in Routt National Forest about a 3 1/2-hour drive northwest of Denver, is the only one of Colorado's three biggest destination ski resorts that has retained a real ambiance of the Old West.

Unlike Vail, which was constructed as an afterthought to the ski area, Steamboat Springs is an authentic, workaday western mining town that also happens to have a world-class skiing mountain.

After a day on the slopes at Aspen or Vail you descend to a forest of fruitwood and fern bars where the ski bunnies parade in the $600 designer-label bib overalls.

In contrast, at the foot of the trails in Steamboat is a simple little four-block main street where the preferred uniform is cowboy boots and non-designer jeans.

At Aspen or Vail, you can slip into a petite hot tub at your rented condo.

At Steamboat, you walk down the main street to the town spa, a big public outdoor pool that is fed directly from an underground hot spring. Some of the finest moments of a Steamboat vacation are spent floating in that wonderfully soothing pool, gazing upward through the billowing steam at the starry heaven and remembering the best runs of the day gone by.

And there are a lot of great runs to remember -- if you are an intermediate or advanced skier.

Steamboat is a giant resort. A gondola and 17 chair lifts, including a quad and six triples, serve seven dozen runs spread over 1,400 acres of Mt. Werner. It is big enough that a curious skier will still be discovering brand-new trails on the last afternoon of a four-day stay.

But only a small portion of this expanse is dedicated to beginning skiers. Steamboat lists 15 percent of its trails as novice slopes. (The figure at Vail is 30 percent, and Aspen has a whole mountain, Buttermilk, just for those who like the skiing easy.) Moreover, Steamboat's novice runs tend to be clustered at the bottom of the lower mountain -- the most crowded spot on the slope, and the area where the snow starts to melt on warm, sunny afternoons at the beginning or end of the season.

There's an advantage, of sorts, in this arrangement: It might give novices at Steamboat a strong incentive to improve their technique to take advantage of the other runs. But if you get your kicks from long, congenial treks down gentle, pretty slopes, you're not going to have a great time at Steamboat.

For those who frequent the "blue" trails, however -- that is, intermediate skiers looking for a challenge -- Steamboat is wonderful.

The wide, fast two-mile-long run called "High Noon," which starts at the 10,000-foot-high tip of Sunshine Peak, is one of the most beautiful ski trails on the continent. Tall stands of Douglas fir, their boughs tufted with white blankets of new snow, provide shade from the bright sun. In the broad valley far below, the skier can see countless streams feeding the headwaters of the Colorado River, which flows from here through the Grand Canyon to a delta in the Gulf of California.

Steamboat also offers a good deal of what is known here as "tree skiing." On runs like "Shadows" and "Sunset," the skier winds downhill through stands of aspen and pine. These runs are quite different from the standard clear, graded ski trail; among other things, tree skiing prompts you to improve your turns.

For my money, though, Steamboat's greatest strength is its long, steep, bumpy expert runs.

Here in macho Colorado, there is an endless argument as to which slope is really the hardest run in the Rockies.

Among the contenders for this honor are the impossibly steep "Pallavicini" at Arapahoe Basin, the three trails known as the "Birds of Prey" at Beaver Creek and the king of the mogul runs, "Drunken Frenchmen" at Winter Park.

Each of these is quite adequate, thank you, to dump just about anybody face down in the snow. But I would argue that there's no run that can match Steamboat's "Avalanche" for sheer terror.

Avalanche, at the top of "The Chutes" in Steamboat's northeast corner, is only about 100 yards long -- but it is 100 yards straight down. The legend holds that nobody has ever skied this hill standing up all the way (it's so steep that once you fall, you have no choice but to sit back and slide ignominiously to the bottom).

Another expert area, but slightly tamer, is the wide area called "The Meadows," where a combination of lots of trees and few skiers makes for a good supply of deep powder almost any time.

But the hottest new item for experts in recent years has been the "bowl," an open, saucer-shaped area with a multitude of runs pouring down the sides.

Steamboat this winter is opening a 400-acre area, "Sunshine Bowl," on the back side of the mountain, with a new triple chair lift to serve this additional space for intermediate and expert skiers.

With this new chair, Steamboat boasts that its total lift capacity is 23,000 skiers per hour, the highest in the Rockies. Nonetheless, you can probably expect some lines -- a half-hour wait is not unusual during busy weeks -- on the gondola and the lifts running up to the lovely "High Noon" run.

Steamboat, in short, is a major-league resort -- and its prices reflect that.

The daily lift ticket for the 1984-85 season, which begins Nov. 21, will be $23 ($21 during two brief "low seasons" at the beginning and end of the winter). This is about as high as any ticket in the country, but still a hair lower than Aspen ($24) or Vail ($25).

Since Steamboat is really too far from anyplace for just a day visit, however, the one-day rate is irrelevant to most people. On a week-long basis, the lift ticket price drops slightly, to about $20 per day.

The resort has a broad range of package plans ranging upward from about $270 per person for a seven-night stay, with six days of skiing included.

The best part of these packages -- and a long-established Steamboat tradition -- is the "Kids Ski Free" offer, in which children under 12 get free lodging and lift tickets when accompanying a grown-up buying a complete package. The resort also provides free ski rentals to kids whose parents are renting.

In Steamboat, you can stay in a modern condominium, a la Vail or Aspen. There's also a modern Sheraton at the base of the mountain, which provides all the standard comforts.

But to stay in one of those places is to miss the real charm of this quaint old western town. The right place to stay in Steamboat is in one of the modest motels downtown near the public spa. Places like the Nite's Rest Motel and the Rabbit Ears Motel offer clean, adequate rooms at $45 per night or so -- about half the fare at the fancy condos at the base of the mountain.

For a rock-bottom Steamboat vacation, there is always the Haystack, a bare-bones motel where "dorm rooms" -- they throw you in with five other people in a room with three bunk beds -- go for $15 per person per night. A private room can be had for about $30, depending on the season.

I have stayed at the Haystack, in times when ski dollars were scarce, and can report that it is at least as good as the spartan "ski dorms" familiar to generations of college kids taking low-budget ski trips to New England.

To get to Steamboat, you aren't really required to drive a pickup truck. The route from Denver's Stapleton Airport follows I-70 west across the Continental Divide at the Eisenhower Memorial Tunnel. At Silverthorne, Colo., just west of the divide, you head north on Rte. 9 for a pleasant 90-mile sojourn through a long river valley. The roughest part of the trip is the climb over 9,000-foot Rabbit Ears Pass, about 20 miles east of the resort. By mid-winter the road here is flanked by two 12-foot high walls of snow left by the plows. The pass becomes impassable fairly quickly during winter storms.

If you don't choose to make the drive, Rocky Mountain Airways flies daily from Denver to Steamboat Springs' little airport ($66 to $100 round trip). And Trailways has an express bus, "The Steamboat Stage," from Stapleton to the ski area ($24 round trip).

If you're really into doing things right, though, get yourself a faded pair of jeans and an old cowboy hat, mount your skis on the back of a four-wheel-drive or a used pickup, and arrive in style at Steamboat Springs -- the western ski resort that is still a plain old western town.