IN THE MIDST of nature's rampage this year, it is possible still to taste samples of her bounty. Oregon has suffered from the ash fallout from Mt St. Helens and has been hurt as well by some emotional fallout. Tourists are staying away. During more than a week in Portland, along the coast and driving south inland, roads and restaurants were uncrowded.

There are plenty of action at roadside markets, however, and with good reason. Oregon is the source of some of the best seafood, vegetables and fruits to be found in this country. Oregon restaurants aren't that different from those found elsewhere, however. Most deep fry almost everything that finds its way into the kitchen. But you can avoid them at mid-day. Buy some foods and eat them at any of the multitude of well-tended picnic grounds in superb natural settings.You can go easy for lunch because this is breakfast country, big breakfast country. There were, for example, fresh blueberry pancakes at the Mallory Hotel in Portland, and memorable hashbrowns and four slices of bacon to a rasher and decent coffee.

Also in Portland, I was served an enormous portion of fresh, heavyweight crayfish at Henry thiele's, a local monument to the restaurants of yesteryear. Thiele's has an enormous menu that offers examples of such diverse cuisines as Viennese and Chinese with little commitment to authenticity. It is another good choice for breakfast, however, particularly if you are partial to potato pancakes in the morning. But don't expect much beyond quantity at the much-publicized Rose's. The lady of that name, who wrote a very successful dessert cookbook, retired some time ago and today the desserts look better than they taste.

But back to basics. In Oregon at this time of year you can find fresh salmon and Dungeness crab, oysters, crayfish and a remarkable creature known as the razor clam. As the name suggests, this clam is thin and sharp -- and full of flavor. They are large, maybe six to eight inches long, and flat with a firm texture. You eat them sauteed, like soft-shell crabs, or in chowders, or in other ways oysters are used in Maryland and Virginia. Smoked salmon and salmon jerky are readily available. But demand for caviar from major cities around the country since the Iranian crisis began has led to sharply escalating prices, increased fishing and poaching of Columbia River sturgeon, according to Portland food and wine authority Matt Kramer.

There were memorable raspberries and blueberries, with other varieties on the bush for roadside picking; apricots and peaches were on sale at the stands, along with lima beans and a specialty from nearby Washington, Walla-Walla onions so sweet and pleasant that you hesitate to cook them. But best of all was something called Seaside peas.

Over the years I've read about them in the writings of James Beard, an Oregon native. His implication, more or less, was that until you've tasted a Seaside pea, you won't know how peas should taste. As usual in such matters, he is right. They are large, but sweet and excedingly tender. A favored way of cooking them is to blanch them in boiling water for no longer than a minute, drain and then saute them briefly in butter. But the favored way of eating them may be raw. At least there was no absence of volunteers when they had to be shelled and the yield per pea that went into the pot was about half the potential. Seaside peas are grown near the small town of Seaside, almost directly west of Portland.They are not exported.

On the other hand, some of Oregon's outstanding fresh fruits and preserves are. The mail-order firm of Hary and David, located in the midst of the rich orchard area, will provice a catalog if you write to them at Medford, Ore. 97501, or call (703-776-2121).

Medford is located near Ashland, the scene of a remarkably successful Shakespeare Festival that has been offered annually since 1935. There are several recommended restaurants in the area, but for a basic meal -- salad, steak and baked potato -- a visitor couldn't do better than the Hungry Woodsman in Medford. It is a dimly lit, overly decorated place that could well be one of the formula chain restaurants. But the quality of the products, the attention to detail and care in cooking make it a winner at a very fair price and illustrate what the founders of chain steak restaurants may have had in mind before they cranked out all those pale carbon copies.

The very best restaurant meal of this, and several other, trips wasn't found in Oregon, however. It came on a short journey into Washington State at the invitation of Yvonne Rothart, food editor of the Portland Oregonian. The place is the Shelburne Restaurant in Seaview, Wash., located about 20 miles north of Astoria, Ore. It's brand new, but located in a funky, 90-year-old hotel also called the Shelburne.

Two talented young women, Jimella Lucas, a chef and once a professional fisherperson, and Nanci Main, a specialist in breads and pastries, are the owners. The restaurant holds about 50 and if it were here in Washington, there would be lines around the block waiting for seats. Not surprisingly, Lucas has a masterful touch with fish. We sampled her steamed clams, shrimp appetizer, sturgeon bordelais, poached salmon and scallops without a single quibble. Yet the best main course dish of all may have been her rendition of Dijon-style chicken. Main's hazlenut cheesecake, a pear flan and Chocolate Decadence with fresh strawberry sauce were on a par with her fine sourdough French bread. In fact the entire presentation, including salads and vegetables, was virtually flawless. If it can keep its act intact, the Shelburne seems certain to be ranked as one of the very best restaurants in the Northwest. The address is P.O. Box 476, Seaview, Wash. 98644. The telephone is (206) 642-4142.