There was no rational reason for a trio of superannuated Boy Scouts to go camping in the Virginia Mountains on a rainy January weekend.

It was Long Tom's fault, really. He had given up Lucky Strikes after a quarter-century of bondage, and was bursting with nervous. He enlisted Patty, who isn't a girl, and Wide Henry, who views camping as the perfect excuse for pigging out on goodies he wouldn't eat in front of his childrenJ.

Wide Henry signed up Slim Jim, a long-legged and woods-wise young man who can be counted on to find trails in the dark and start fires in the rain and splint broken legs. Also, he has a tent that doesn't leak and straps on his pack.

The trail chosen was over Massanutten Mountain from jack's Notch to Kennedy Peak, which has the virtues of being short, fairly easy and surrounded by civilization, so that if you fall off the mountain you'll probably roll into somebody's back yard.

Wide Henry and Slim Jim had done the same stretch last January with a bunch of overenthusiastic and underprepared members of a hiking club, some of whom very nearly went into hypothermia when the cold front that brough last winter's big freeze caught them dawdling on the trail.

This year Wide Henry spent a week gathering supplies, making a list and checking it twice, working on the assumptions that it would come on a blizzard and that nobody else would remember to bring food. He did not neglect to pack along Bradford Angier's "How to Stay Alive in the Woods." (Eat the whole moose, it advises.) Slim Jim never forgets anything, and Long Tom and Patty brought two or three of everything, having gone hog wild in a couple of camping departments.

And before hitting the trail they checked in with joe Sottosanti, who lives on the Massanutten above Luray and tries to see to it that who goes up also comes down. "Try and make it back before dark Sunday this time," he said. "That search party I got up and home. Nothing worse than a posses with nobody to chase after. Three of them wound up divorced, and another one still isn't speaking to his dog."

Three hundred yards up the trail, or rather up the mountain on what Sottosanti had promised was a shortcut to the trail, Long Tom began to develop a passionate interest in moss and lichens, which he discovered while he was bending over in search of his breath. Within half a mile he had infected Patty and Wide Henry, and all began to scan the sodden forest floor for things to pause and appreciate. After one long barren stretch that left them gasping and blowing, Wide Henry pockected a mossy rock, which he thereafter surreptitiously placed on the ground as needed.

"Funny how this kind always seems to grow on a particular size and shape of stone," patty wheezed.

"Must be critical to its microclimate," panted Long Tom.

Slim Jim, meanwhile, was ranging far ahead, striding over the ground on his muscular legs, unmindful of the weight of his sensibly supplied and property balanced pack, impatient to see what lay over yonder ridge. We kept track of him by the glint of his glasses.

"Had a dog like that once," Long Tom said while we were sitting down with packs shed, the better to examine an especially timely colony of fuzzy rocks. "Take him out in the woods and he'd go stone native. Frisking through the bosky dell, filled with joie de vivre, tireless, investigating every sight and scent, careless of my commands, poetry in motion as his silken coat streamed in the wind of his own passage."

"Sounds like a hell of a dog," Patty said.

"What became of him?"

"Shot the bastard in self-defense."

Half an hour on the trail - and fully two hours since breakfast at Daddy Bill's Cafe in Luray - Wide Henry began to whimper about lunch. "Best thing to do when you're on the trail in the cold is keep snacking," he said. "All the real hikers say that."

Long Tom was nothing loath to launch lunch, but Patty suggested that "As a matter of form, shouldn't we wait until we're out of sight of Sottosanti's?"

From time to time Slim Jim would appear, now above us, now below, always moving fast and never breathing hard. It was particularly frustrating to Patty, whose slicksoled boots cost him two backslips for every three strides ahead. His singular gait, suggestive of a hunchbacked bear on a rolling ball, moved his companions to giggles they could ill afford.

Shamed by Slim Jim's example, we pressed on until noon, when he shouted down from a gentle rise that he had found the campsite (selected in advance from the map Wide Henry managed to lose after a mile on the trail). By one o'clock we had joined Slim Jim. Revived by the lunch he had prepared, Long Tom and Wide Henry busied themselves cooking another on camp stoves while Patty started starting a fire.

The tents went up in jig time, which seemed to disappoint Slim Jim. "It doesn't really count as winter camping when you can push the tent pegs into the ground," he said. "Maybe we'll get some snow later, or some wind." He kept checking his thermometer through the weekend, but never could get it to go below 35.

Through the afternoon we spelled each other, cooking lunches and starting the fire, while Slim Jim practiced his rock climbing on the ridges between Strasburg and the Pennsylvania border.

"Hurry up and eat the rest of the beef Stroganoff," Long Tom urged as darkness fell over Patty and Wide Henry, who still were starting the fire. "It's dinnertime and I need the pot." Slim JIm came ballooing back and started the fire by rubbing two damp trees together.

The intervals between dinners were filled with crackers and candy and cognac and Calvados, which passed around the campfire in company with the lies. Long Tom, who had brought along a pack of Lucky Strikes to show that he wasn't running away from the fight, smoked several to demonstrate that he could take them or leave them alone. "One must never fear to face the enemy," he instructed us.

From time to time things went bump in the surrounding circle of dark. Nothing could be seen out there, even when the bright end of the flashlight was pointed toward the source of the sound. Motions were made to mount a party of inquiry, and a nominating committee was formed. All nominees pleaded the press of other duties, such as counting the forks, and the matter was tabled.

Around midnight Wide Henry served out another round of steaming Sierra cups. "That tasted a little odd," patty said. "What was it?"

"Cream of Wheat. We seem to be all out of dinners."

"The chicken Pilaf? The vegetable stew? The macacroni and whatsit? The scampi Provencale? The tuna noodle casserole? The Salisbury steaks? The turkey Tetrazzini? The chicken with rice? The beff with snow peas? The Welsh rarebit?"

"Gone. All gone. The cognac too. And the Polish strawberry wine."

Long Tom searched his emergency supplies and found a backup package of freeze-dried beef Wellington, but then it began to rain harder, so we crawled into the tents.

As the fire hissed lower the bumping grew louder and nearer, but then Wide Henry began to snore and the others stopped worrying aout unknown perils. In the morning, 10 yards from the tents, we found saplings torn and the ground trampled where a buck had been cavorting in celebration of the end of deer season.

The others rose at dawn ("You observed archly) but Wide Henry slept through the first two sittings of breakfast. he mumbled vain protests as the others struck camp while he was trying to catch up.

Slim Jim had gone foraging for walking sticks. "They're like another leg," he said. "I would have cut you guys two each, but I figured you would need one hand free for eating." For himself he had selected a stout staff of ironwood, which he occasionally employed to good effect when we lingered too long over the lichens with which God has graced the spine of Massanutten.

We stumbled along in the blowing mist for a mile, two miles, yea, three miles and more, snatching glimpses of the neat farms of the Shenandoah Valley between intervals of rain.

TFrom time to time Slim Jim would appear out of the gray void, prophesying doom to stragglers and lichen freaks, occasionally tanalizing us with word of gentler grades ahead - even, now and then, a downhill stretch in which we gloried until the time came to win back the squandered elevation."

"If he shows up with a pair of stone tablets I'm going to just die," Patty said.

"I may die anyway," Long Tom gasped. "Wide Henry, keep your pencil handy, because I have some last words I've been working on, a verse for my epitaph. What rhymes with 'Xerxes'?"

There was a silence punctuated by heavy breathing and the crunching of candy."Long Tom, I guess you better suck u up and keep on keeping on," Patty said at last. "Nothing rhymes with Xerxes.

"Or would you settle for just the name and dates and selected highlights?"

"I am determined that my tombstone shall draw a smile or a tear from the passing stranger," Long Tom said, shouldering his pack and striding up the trail with renewed resolution for a yard or two until he bumped into the Kennedy peak shelter, where Slim Jim had finished his lunch and was polishing off the one he had prepared for us.

"Downhill all the way from here, tigers," he said.

And it was, with a couple of trifling exeptions. Which wa a good thing, because we never did come up with a rhyme for Xerxes.