The streets around National Guard Armory were swarming yesterday with people wearing glazed expressions and carrying dead trout.

The trout came from a fishpond set up at the Recreational Vehicle and Outdoor Show, which opened yesterday and will run through Sunday next. The glazed expressions came from wandering through acres of recreational vehicles that ranged from $500 camper caps for pickup in which everything is automatic but the driving.

The public missed one of the best parts of the show. It was the Marx Brother-style traffic jam that developed when the exhibitors arriving earlier in the week ran into the preparations for the Inaugural party, a division of which was held at the Armory.

Many of the exhibitors were locked out of the building and a few were locked inside, according to a show spokesman, because of conflicting orders by the Secret Service and National Guard.

"Then the Army wouldn't move their trucks out to make room for the RVs," he said. "Told us to park 'em on the street. Hoo Hah. Some of the guys just camped out in the things for a couple of nights, and one of them got a ticket."

Hardly a peanut shell remained from Jimmy Carter's gala when Redskin quarterback Joe Theismann opened the show at 1 p.m. yesterday.

If the energy crisis and the threat of runaway gasoline prices threatens to bust the RV boom, the word doesn't seem to have reached the manufacturers. The only mention of gas mileage and other operating costs was the sticker on a baby Chevy van that claimed 31 miles per gallon on the highway.

The salesman for a six-ton, $30,000 travel home winced when asked about mileage. "Don't ask," he said. "Eight, maybe more or less. Depends on how you drive. Stop-and-go, or a long haul in the mountains, who knows? But she carries 90 gallons of gas with the optional 40-gallon tank, so you've got the range if you've got the change."

Things were slow at the trout pool until they started passing out the salmon eggs. "A few minutes ago they wouldn't hit anything but bacon rind; I don't know what makes them change their minds," the attendant said. The fishing is free for children. $1 for 10 minutes for adults, results not guaranteed.

"Oh, I want to put him back," one small boy said when a trout fell for him. His father regarded the flopping fish. "I'm afraid he's going to die anyway. We'll take him home and you can have him for breakfast."

"Ick," the boy said.

In a fittingly quiet corner of the basement some young boys in the employ of Angler's Art were embarrassing their elders by demonstrating how easy it is to tie a fly. On a nearby table were dozens of irresistable sportsmen's books, including two gentle frauds whose thesis was that it is in fact possible to bag a turkey.

About a quarter of the exhibits involve boats and camping gear for people who actually walk, reflecting an attempt by Mid-Atlantic Expositions, Inc., "to broaden our appeal.There are a heck of a lot of people who just aren't ready for a big RV investment, and we're trying to present alternatives!"

For the commuter who lusts after those boats he sees curising on the Potomac while he's on the way to work, the Yukon Delta houseboat exhibit is particularly cruel.

The company is showing boats ranging from 25 to 32 feet and from $5,000 to $19,000, depending on options such as a fur-lined bow cubbyhole and a flying bridge that puts the captain on a towering throne."

"Think of it," a salesperson purred. "Come Friday afternoon you just pull the dock plug, light her off and say he hell with it."

Until the loan company that nasty note.