When it comes to furnishing wholesome outdoor recreation, the national parks surely rank among the finest vacationlands on earth. But crowds and creeping urbaniztion, prevalent at the core of such renowned areas as the Grand Canyon, Yellowstone and Yosemite, defeat the very purposes that attract visitors in the first place.

It's little wonder, therefore, that steadily rising numbers of Americans are asking "Where can we go to escape the crowds? Where are the national parks with space and elbow room?"

The questions are valid, but the answer is not simply a matter of where but of how - to look at national parks as sanctuaries or special places, how to appreciate and absorb the wonders of nature that they preserve, how to reorient one's own travel patterns.

In a way, the director of the National Park Service, William J. Whalen, has lately given a clue - though not exactly intended as such. A memorandum to field personnel that could easily be directed to the public reads as follows:

"Look closely, in every park, for opportunities to provide visitors with ways to enjoy the contemplative pleasures that are so often at the heart of what we like to call 'park values.' For example, a short, easy pathway to a quiet spot away from the crowd can be a non - threatening and delightful bridge from the urban scene to the brink of wilderness. And give the visitors a chance to people historic structures with their imaginations - free of messages, signs and chatter."

Let's call this the unhurried approach. It seems particularly fitting in this age of fuel shortage, which may even prove to be a blessing in disguise. Until now speed, which demands high energy output, has been a predominant value in itself. The object has been to see how lightly you can pack your wash - and - wears and medicines, then to cover 10 countries in 10 days, or a dozen national parks if you're traveling in the West.

But those who cover 500 miles in a day (or who zip from one capital to another) return only with picture postcard images and in need of rest. They may make it through the parks, but touching only the centers with little chance to explore the uncrowded, unhurried corners.

A slower pace expands the dimensions of time, especially in a natural enviroment. It isn't a question of how extensively or expensively you travel but how intensively and perceptively. Visiting fewer parks and staying longer at each leads to better appreciation and more enjoyment. Once you've arrived, the use of self - generated energy by walking or bicycling helps, too. So does canoeing. It costs little, pollutes nothing, is great for bridwatching and nature study and the exercise is beneficial.

That's what national parks are all about. They're more than tourist attractions in the ordinary sense, but communities of native life, safeguarded so that visitors may understand the mechanism of natural systems, and learn to respect it.The parks have proven their value many times over as sanctuaries of nature, but they are sanctuaries of man as well, affording respite from sights, sounds, smells and pressures of a technological supercivilization.

Getting the most out of this type of experience requires time and patience. Motorists may whiz along U.S. 101, the Redwood Highway in northern California, and think they have seen the redwoods (or the landscape of any park in which they're travelling), but they haven't scratched the surface. Only by getting off the main road and wandering afoot in a secluded grove can you fully appreciate the meaning of these tallest living creatures on eartth.

In a redwood grove low shafts of sunlights slant through the leaves, revealing a luxuriant botanical garden. By walking only a short distance from the main paths, the visitor can find solitude and become his own ecologist. It's astonishing how you can train your eyes to notes things others ignore - for example, that the redwoods never grow alone, but in company with other trees and with a lush undergrowth of plants, lichens, ferns and moss.

Often it's the concept of little things, rather than the spectaculars, that counts most. As massive monuments to the forces of nature, the peaks of the Rockies, the Sierra Nevada Range, or Mount McKinley in Alaska delight the eye, but perhaps there's as mush majesty, of a more intimate kind, in the humble lichens, mosses, tough grasses and sedges - a variety of dwarfed, matlike plants capabel of surviving in serve climate and producing a surprising display during their brief seasons in bloom.

Consider the weather, which modern travelers are conditioned to expect to be just right - based on human standards, of course. Yet fog and rain are nourishment upon the earth, creating magic moods and mysteries in the process. As Thoreau expressed his choice of seasons at Cape Cod (now a national seashore):"A storm in the fall or winter is the best time to visit it."

The ideal experience is to feel as part of nature, rather than to view it through a picture window in padded comfort. An experience in the weather, or even sensitivity to it, helps develop the harmonious naturalist view. It's the kinds of thing that comes with practice and patience, searching for deeper values through intimate explorations.

Time of day has a lot to do with things, too. Twilight, morning or evening, makes a choice time to walk. It's uncrowded. In some parks it's a witching hour when deer feed on open hillsides and coyotes serenada the skies. Early morning and evening usually are the best times for birdwatching, a pursuit that leads you away form traffic and out of your car, that sharpens your senses to all things in nature.

Yes, parks are crowded, but mostly at the core areas where people seem to congregate because they are used to urban ways. The problem is caused not strictly by the capacity being exceeded, but by too many bodies jamming into too few of the most scenic spots and degrading the scenery in the process. The central points get the pressure while the back country is less apt to fill up.

In terms of campgrounds, once you get off the paved roads space becomes more availanle, and when you opt for an area with pit - toilet instead of flush toilet it's even more so, particularly if you hike in. You've not only found the uncrowded quarters but are using the nature sanctuaries as they were intended.

Those who still desire to visit the less crowded" parks will do well to direct their attention to areas like Theodore Roosevelt National Park, a jewel amid the buttes, gorges and canyons carved by the Little Missouri River in the Badlands of North Dakota. Most vacationers find it too far off the main tourist routes, leading through the Black Hills of South Dakota into Yellowstone, but that's exactly what makes Roosevelt more appealing. It's a park where you can wake in the morning at the Cottonwood Canyon campground to hear the coyotes howl, then visit prairie dog towns, watch herds of bison roaming freely and follow Theodore Roosevelt's career as a young rancher. The birdwatching possibilities are tops.

This particular area was redesignated as a national park in 1978, though its resources haven't changed a bit since memorial park. The National Park System actually covers more than 300 units in all parts of the country - variously called parks, monuments, seashores, lakeshores, recreation areas, river, battlefield parks and parkways - and you don't have to cross the continent to find one.

The Obed National Scenic River, on the Cumberland Plateau in Tennessee, as a case in point, embraces some of the msot striking wilderness scenery in the Southeast. Cuyahoga Valley National Recreation Area, Ohio, preserves a parcel of nature and history between the heaily populated metro areas of Cleveland and Akron. And even in New York, the Jameaica Bay unit of Gateway National Recreation Area contains a 6,000 - acre wildlife refuge, one of the few reserves of its kind accessible by sunway and bus. There's enough of nature in the saltwater marsh, with its 200 species of birds and small animals, to hold anyone's attention.

What makes a national park area truly special is the quality of human experience it offers. Four years ago the superintendent of the Great Smoky Mountains National Park, in North Carolina and Tennessee, decided to focus on this particular point. Superintendent Boyd Evison (now an assistant director of the bureau in Washington) placed the emphasis on camping for self - reliant tenters who walk to their sites rather than for drivers of self - contained recreational vehicles, whose needs can be met as well or better outside the park. (Private campgrounds, after all, are equipped to provide conveniences and to accept long - term reservations).

Instead of building roads, Evison closed roads wherever possible, turning them into "quiet walkways." There is now plenty of chance for solitude and reflection on these travils - even through Great Smoky Mountains park is the most popular and heavily visited of all national parks.

Those who may have felt discouraged about visiting the parks should now take heart. With planning and the proper point of view, all else will follow. CAPTION: Picture 1, Off the road and on foot in Montana's Glacier National Park; Picture 2, Off the crowded roads, tourists can find the real splendor of the redwoods.