Time again for one of the year's big decisions. Where's the family going to spend its summer vacation? Not a question to be taken lightly, especially in workaholic Washington. Summer vacations possess a mystical quality, imbued with winter-born dreams of outdoor pleasures under a sparkling sun. They are also an uninterrupted opportunity for parents and offspring to enjoy each other's company under the most advantageous circumstances.

But like anything that's important, family vacations take thought and planning and the kind of research you put into any purchase that costs hundreds or even thousands of dollars. They can be a gamble, too, ending perhaps in irritable squabbles instead of pleasant memories.

Many Washington families head for the beach each summer, and that's a near-perfect family vacation if nobody minds sand in the swimming suit. Only when the rain falls for a second day do the spats begin to erupt.

Now, there's certainly no way to guarantee a good time for everyone, no matter what the vacation, but we've picked six other holidays made-to-order for outdoor family fun -- holidays that offer a change of pace, new vistas and the shared fun and camaradarie of learning new skills together. The vacations include a trip to a nearby Virginia mountain getaway, a couple of exciting wilderness adventures and a lodging bargain in a famous Rocky Mountain resort.

The possibilities for family vacations are endless, given the infinite variety of interests of American parents and their children. But parents with plenty of traveling experience suggest rethinking any plans for sightseeing trips by car, especially with younger children, and that advice is good. The potential for discord climbs as the wearying miles and hours continue to mount.

And what seems a dream vacation can have a disappointing outcome, as this story illustrates: The scene is a lovely Caribbean island, where Mom and Dad are having the time of their lives floating in a warm blue sea. That is, until their teen-age daughter begins to whimper.

"Can't we go home?" she urges. "It's so boring here." The problem, it turns out, is that she's about 15 years younger than anybody else around, and she would much rather be back home with her friends.

A trip that appeals to the parents (the stately old homes of England) may not enthuse their children, and vice versa. Wise parents save their dream vacations for themselves (or until their children are older) and try to find something else the whole family will enjoy.

Compromises may be in order, but a happy solution is to go where there is a wide enough variety of activities to keep everyone entertained. A good possibility is an out-of-doors holiday, one with lots of physical activity but also with good food, time to relax and some interesting (and educational) things to see.

The energetic can keep going as long as they last; the dreamers will find a cozy corner to read a book.

The trip also should offer plenty of opportunities for the family to spend time together -- a major purpose of the holiday, after all. But as the children get older, they will want free time to go their separate ways. In a car, there's no escaping one another.

And families (single- or two-parent) should consider vacationing in places where other families go, especially with younger children. That way, the youngsters can find company their own age. It's surprising how a couple of new acquaintances can enliven a holiday and keep everyone on best behavior.

Here are six special family vacations that should delight young and old alike:

BRYCE RESORT, Basye, Va.: Small, friendly and attractive, Bryce Resort is nestled in a scenic valley surrounded by the wooded slopes of the Shenandoah Mountains. Among the many sports-oriented resorts that have sprouted in the past two decades within a few hours' drive of Washington, it offers one of the widest choices of summer activities.

In the mountain quiet, vacationers can escape the crowds, the noise and the traffic of the Atlantic Coast beaches. Nearby is a historic Civil War battlefield at New Market, underground caves open for tours and the trails and vistas of Shenandoah National Park.

Bryce is one of the region's oldest all-season resorts. It is managed by an athletic pair of Bavarian-born brothers, Manfred and Horst Locher, who were attracted by the winter sports but subsequently have put the resort on the world map of summer grass skiing.

Beginning May 25, the resort rents out a special kind of short skis on rotating treads that send you racing down the same slopes that challenge winter skiers, but you are whipping over well-clipped turf instead of snow. The skiing technique is much the same either season, but with one big difference: The snow is softer when you tumble. (Sunday only 9:30 a.m. to 12:30 p.m. until July 7; then also 5:30 to 8:30 p.m., Monday, Wednesday, Thursday and Saturday through Aug. 29.)

More recently, Bryce has added wind surfing (lessons and rentals) on Lake Laura, a 45-acre man-made gem that warms wonderfully by August. That's important because beginners spend a lot of time in the water. Parents and older children (generally 12 and up) can learn together.

Traditional sports include swimming and canoeing on the lake; swimming in the large outdoor pool; an 18-hole golf course; horseback riding on lakeside trails; fishing in the lake and streams; tennis (with three of seven courts lighted) and hiking in the surrounding George Washington National Forest. Special programs for youngsters and teens are planned throughout the summer.

At the foot of the chairlifts are a large, comfortable restaurant, a snack bar and a cocktail lounge, the Copper Kettle.

Accommodations are in condominium apartments, townhouses and mountain or lakeside chalets, all of them equipped with kitchens. Families can save substantially by preparing many of their own meals.

A modern two-bedroom condo at Bryce Hill near (but not on) the lake rents for $65 a night for two people, plus $7.50 for each additional adult or child; the weekly rate is $50 a night for two. A townhouse on the valley floor (about 1.5 miles from the lake and pool) rents for $85 a night weekdays and $105 on Saturday and Sunday.

Chalets, depending on size, range from $120 to $175 a night, with a two-night minimum. A two-bedroom (with loft) on Lake Laura that sleeps six costs $135 a night.

Most recreation facilities are extra. A seven-day "recreation fun pass" for tennis, swimming and grass skiing is $48 per person for adults and children.

Reasonably compact, despite the 1.5-mile distance separating the lake and the skiing facilities, Bryce is an easygoing, informal place. Only two hours west of Washington via interstates 66 and 81 (travelers save on transportation costs), it nevertheless is a world apart.

Arrive, unpack and plunge into a rigorous whirlwind of sports. Or indulge in long afternoon naps on the deck, sniffing the mountain air, while the rest of the family is busy elsewhere.

For more information: Bryce Resort, P.O. Box 3, Basye, Va. 22810, (703) 856-2121.

WILDERNESS CANOEING, Ely, Minn.: This four-night, five-day canoeing and tent-camping trip through the Boundary Waters Canoe Area, a wilderness region in northern Minnesota, has been designed especially for families with children 6 and older.

"It's the whole roughing-it experience" -- for beginners as well as practiced outdoors families, says Patsy Fleming of the American Wilderness Alliance, a Colorado-based conservation organization that sponsors an annual series of 80 wilderness trips, most of them open to families. Participants learn about the preservation of the Boundary Waters area, and instruction is given in proper "low-impact" camping techniques. The tour is limited to 16 people, two passengers plus gear to a canoe.

The canoeing distance is not long -- about 30 miles total -- and there is a leisurely layover in camp every other day. The departure date from Ely is Aug. 12, when, says Fleming, "the mosquitoes are gone and the fish are still biting." The water generally is calm, so there are lots of chances for swimming. River creatures from otter to moose may be spotted as the canoes glide past the shore.

The guides set up camp and prepare the meals -- fresh foods are packed along -- though participants frequently volunteer to help, maybe because dinner gets served faster that way. The price from Ely is $380 for adults and $235 for children 12 and younger. The figures includes meals, tent, sleeping bag, pad and instructional canoe practice just prior to departure.

Trips such as this, in which there is a shared challenge, can forge a strong bond among participants -- between family members as well as new acquaintances, who may become lasting friends.

A wilderness outing is also a reminder that there is life beyond the stereo and TV sets.

For information about this and other wilderness trips: American Wilderness Alliance, 7600 East Arapahoe Rd., Suite 114, Englewood, Colo. 80112, (303) 771-0380.

SNOWMASS, Colo.: The setting is the rugged Rocky Mountain West, but the lodgings border on the swank for families who would just as soon have a roof over their heads and a modern toilet and a hot shower handy.

Snowmass, just 12 miles northwest of the famed ski town of Aspen, is a winter resort that can be just as much fun in the summer. At an 8,000-foot elevation, days are mild and the humidity is low, perfect for strenuous outdoor activity. Nights are cool, so you might want to build a fire.

An excellent hiking trail a short drive away leads into the Maroon Bells-Snowmass Wilderness. It climbs two miles from the trailhead at Maroon Lake up to Crater Lake amid majestic snow-capped mountain scenery. You can pack along a picnic for a not-too-strenuous half-day's round trip. Outfitters organize mountain trail rides, high-country jeep tours and white-water rafting adventures.

Adjacent to Snowmass is an 18-hole golf course; there are 13 courts in the Tennis Garden; and scattered among the condos and lodges are 47 swimming pools and hot tub spas, if anyone is counting.

Both Aspen and Snowmass are famed for fine dining, but there's also a good selection of less expensive family and fast-food establishments. Movies, theater, concerts, ballet and other cultural events fill the summer calendar in both resorts.

A two-bedroom condominium sleeping four at Snowmass begins at about $85 a night. But a special coupon promotional deal in the May 21 issue of Family Circle magazine offers one night free for every night purchased (two-night minimum). That means four nights for the price of two, a rate for a classy resort that rivals the price of a highway motel. Purchase a full week's lodging, and the second week is free.

For more information: Snowmass Resort Association Central Reservations, P.O. Box 5566, Snowmass Village, Colo. 81615, (303) 923-2010.

INDIAN COUNTRY, Arizona: Navajo guides lead a group of 16 hikers and campers (8 years and older) on a week-long trip into the remarkable Canyon de Chelly National Monument, a deep canyon within red-rock cliffs in the heart of Arizona's Navajo Country.

Described as a "Navajo Cultural Experience," the trip is one of a half-dozen outings organized especially for families by the Sierra Club, the national conservation organization. (Other trips climb into California's Sierras or explore Channel Islands National Park off the Santa Barbara, Calif., coast.)

Meeting in Chinle, Ariz., the group descends 1,000 feet from the canyon rim to the tree-filled valley, watered by a wide but very shallow river. On weekends, Navajo families flock to the mouth of the canyon, a tribal preserve with controlled access to outsiders, splashing their four-wheel-drive trucks through the water to picnic sites. It's a fascinating opportunity to observe, discreetly, families from another culture at play.

On the trip, participants also will have a chance to watch Navajo weaving, sand painting and dancing. The canyon is the site of ancient Anasazi cliff dwellings, accessible and well-preserved, and colorful rock paintings.

The hiking is leisurely, and there are layover days at the campsites. Hikers are expected to carry 20 pounds of personal gear, but food and water will be trucked in.

Adults and older children are expected to pitch in with the cooking and cleanup chores, but on a camping trip that becomes part of the fun. It's quite an education for urban youngsters (or their parents, for that matter) to cope without the electrical conveniences of modern life.

The canyon trip is scheduled for Aug. 2-9. The price for two parents and one child is $935 from Chinle; for one parent and a child, $605. Each additional child is $235. This includes meals and cooking equipment; participants must provide sleeping bag and tent.

For more information: Sierra Club Outings 1985, 530 Bush St., San Francisco, Calif. 94108, (415) 981-8634.

BICYCLING, U.S.A.: Nowadays, you can tour practically any part of the United States (and Europe) on an inn-to-inn bicycling excursion. Several local tour companies offer trips on Maryland's Eastern Shore and in the Allegheny and Shenandoah foothills west of Washington.

For families with older children (generally 8 and older), they are an excellent way to see new sights while enjoying a favorite out-of-doors recreation. A van totes the luggage and is available for on-the-road repairs, so all you have to do is cycle.

Actors Paul Newman and Joanne Woodward took their five daughters cycling in Vermont last summer with Vermont Bicycle Touring, which advertises that it is "the originator of country inn bicycling vacations." This is the firm's 14th season.

Actually, the Newman/Woodward trip was a family reunion, says company founder John S. Freidin, who led their tour, since the daughters range in age from late teens to early 30s.

They chose VBT's "Weathersfield Wanderer," a five-day, low-mileage ramble through the river valleys of southern Vermont. On this trip, there's a stop two afternoons for tennis, and swimming is possible every day at such quaintly named New England places as Echo Lake, Stoughton Pond and Buttermilk Falls. One of the inns features a sauna, good for well-worked muscles.

The Weathersfield trips depart frequently from mid-May to mid-October. The price is $379 or $429 per person (depending on departure dates), which includes lodging, breakfast and dinner. You can bring your own bike or rent one for $69/$79.

For more information: Vermont Bicycle Touring, Box 711-RF, Bristol, Vt. 05443, (802) 453-4811. Bicycle USA publishes an annual directory of 142 bicycling tour operators. To obtain a copy, send $2 to Bicycle USA, Suite 209, 6707 Whitestone Rd., Baltimore, Md. 21207.

THE RANCH LIFE, Montana: This is the kind of vacation that appeals to young and old who want to relive the Cowboy West. The choice of guest ranches ranges from plush dude resort (heated pool, tennis courts, fine dining) to authentic working spreads, where guests pitch in with the chores and enjoy hearty ranch-hand fare served family style.

Among the last category is the Sweet Grass Ranch, at road's end 40 miles from Big Timber, Mont. It is a 10,000-acre cattle and horse-raising ranch that has been in the Carroccia family for five generations. The four Carroccia children, ages 12 to 20, are among the wranglers keeping an eye on city dudes learning to ride the range. They will instruct anyone interested in how to ride bareback.

Sweet Grass Creek tumbles through the ranch, which is located at 6,100 feet in the Crazy Mountains. Riding is over open range or up mountain trails to 10,000 feet past four or five mountain lakes.

About 30 guests are accommodated at a time. They can watch, or join in, such typical ranch activities as branding, cutting hay, checking the fences on horseback or driving cattle. "The young cows," says Shelly Carroccia, "are not easy to move," so some working days can be long. Once she brought a group back in at midnight; and the chores get done rain or shine.

"When they leave a ranch, they know what it's like to live on one," she says of her guests.

But there's time off, too, for trout fishing, moonlight rides, cookouts, hiking and visits to nearby ghost towns and rodeos.

Lodging is in three cabins with private bath, $365 per person a week for guests age 6 and older; five cabins with a shared shower house, $325 per person; and five rooms with shared bath in the main house, $345 per person. For children 3 to 5, the charge is $200 a week. The price includes seven nights lodging, three meals a day and horseback riding daily except Sunday. Open this year from June 15 to the end of the third week in August.

For more information: Sweet Grass Ranch, Melville Route, Big Timber, Mont. 59011, (406) 537-4497; in summer, (406) 537-4477. A directory of 63 selected ranches can be obtained from The Dude Ranchers' Association, P.O. Box 471, Laporte, Colo. 80535, (303) 493-7623.