The elemental mysteries of life are a breeze for Dan Zavisza. In his workday world as a chemist, Zavisza solves proton puzzles too small for the eye to see. So it is only fitting that this Frederick, Md., man should be standing on sand in the rain, peering through foggy spectacles at his J.C. Penney tent as though it were some beast from beneath the sea.

"I'm sure this is the peak," says Zavisza, holding a pole in one hand and a formless bunch of orange nylon in the other while his wife Jean does her best to hold her own pole and a laugh. "We'll keep trying till we get it right."

Before the weekend is over there will be more than balky tents to test the Zaviszas' pioneering spirit. Mosquitoes large enough to carry off a small child will descend upon them. Green-headed flies capable of chewing through sheet metal will attack in packs. And when their exposed flesh gets uncomfortably rain-soaked, the sun will appear to burn it off their backs.

At Cape Henlopen State Park, a lovely oceanside campground, this weekend will provide all of the ingredients that make camping both agony and ecstasy. One consolation to the people prompt enough to reserve one of the park's 160 coveted campsites is that they are not 75 miles further down the Atlantic coast at Assateague where National Nude Weekend is being commemorated by a few hundred "naturists" with less protection and more to peel.

"This has the worst of both worlds," says Tuck Garvey, a 26-year-old mechanic from Wilmington, Del., who is camped out beside his Volkswagen van with his dog Useless. "There is no electricity and you still have people all around you."

Even dedicated homebodies will concede that camping has its virtues. Chief among them may be the right it gives you to complain. Grouse about the brown spots in your back yard or the high cost of air conditioning at a party and someone is likely to brand a giant B for boring on your forehead. But get away for a weekend in the wilderness and you are almost certain to bring back enough tales of woe to enthrall your friends for months.

"Have you ever gotten up in the woods on a Sunday morning when it's pouring rain to cook breakfast? It's the pits," says Bart Barnes, a friend and colleague who abandoned his wife in their tent in the middle of the night a few weekends ago to sleep in the car. "I hadn't been camping since the Army. And I don't ever intend to do it again."

As long as we're talking about trouble, we might as well mention sand. After a weekend on the beach, many a camper would be willing to fight a hungry bear for a sandwich without sand. And the bugs that find sand a pleasant home are generally not the kind you'd invite into yours.

"I'm just covered with bites from these sand fleas," says Sid Barsky, an art supply wholesaler from Montreal who has camped with his family from one end of North America to the other during the last 23 years. This year he is in Delaware, trying to forget the money he lost in business last year. The sand fleas provide a ready scapegoat. "Somebody has to get rid of 'em."

"This place has every bug known to man," says Bill Jones, a 30-year-old lawyer from Pennsylvania who is sitting on an aluminum lawn chair a few campsites from Barsky. Jones is not complaining, just making an observation. He loves beach camping enough to drive down every weekend. He will tell you about the pounding surf under starlit skies and camaraderie among the sand dunes. It is beautiful, says Jones, close to Rehoboth's boardwalk and night spots. And very cheap.

"We can stay here for 10 days for about what it costs for one night in a place at Ocean City," says Hearl Condon. He and his wife Ruby have staked out a site for their trailer just yards away from a modern bath house in the park. For $7 a night, they have an ocean to swim in, a mile and a half long fishing pier, tennis courts, even a frisbee golf course. The Condons, from Taylorsville, Md., prefer to sit in lawn chairs, under a tarp, near enough to their trailer to retire at the first sign of an enemy air attack. "This is what you look for when you go camping. That's why the sign at the gatehouse says 'Camp full.' "

Marcia Wieder is disappointed in the Condons. This Long Island native thinks camping in a mobile home is cheating. "They bring everything with them," says Wieder, who had a score of romantic fantasies crushed when she went on her first camping trip last year. "I wanted to sit around spitting into the campfire and roasting marshmallows. Everybody laughed at me."

Loren and Marilyn Green still camp the old fashioned way. They first came to Henlopen as Scout leaders in 1962. This weekend, with a few grandchildren along, they are back sleeping in the same faded green tent they used then. "You can see the patch of new material on the side where the bear crashed through," says Loren, whose red hair and beard are streaked with gray.

But even the Greens, hardy as they are, concede that beach camping has its disadvantages. Loren is "very susceptible to bugs that bite" and most of them at the beach do. Marilyn says she has trouble coping with both the hot sun and high humidity. The more they talk, the more they find to dislike.

Finally, fanning herself with a piece of note paper, Marilyn Green whispers a confession, "I'd trade this for a week in an air-conditioned condominium anytime."