Ollan Cassell, executive director of the U.S. Amateur Athletic Union, was running around Moscow last week, checking out hotels and tourist facilities.

"We have a tour coming over next summer for the Olympics," he said, "and we're trying to find the best accommodations."

Good luck, old boy.

As executives of NBC-TV already have discovered, to their dismay, entertaining high-rolling clients, guests and VIPS in the manner to which they are accustomed is difficult in the Soviet Union.

Moscow has its sightseeing attractions. The Kremlin, for instance, should not be missed. The city is rich in caviar and champagne (but beware the wicked hangover), and in ballet, opera, circus, puppet theater and other performing arts.

However, it is decidedly lacking in haute cuisine, night life and the other trappings of "expense account living." As for plush digs and traditional Western diversions . . . would you care to stop in Vienna on the way home?

First of all, there is a shortage of hotel rooms in the Soviet capital, especially those Westerners would consider luxurious. Deluxe in Moscow means the porter has not made off with your toilet seat, a hard-to-get consumer item in great demand here.

Moscow's first international four-star hotel, the 28-story Cosmos, opened last month. It was built by a French firm, which spent three years completing the $170 million project entirely with imported materials and French and Yugoslav labor.

Commissioned because of Soviet-built hotels have not measured up to world standards, the Cosmos will be Olympic headquarters for International Olympic Committee officials and their guests, plus television bigwigs.

Five new domestic hotels with more than 27,000 beds will be completed before the start of the Games next July 19. Even that will not be enough to house the 600,000 tourists (more than 300,000 from abroad), 5,000 sports officials and 8,000 journalists coming here for the Olympics.

"It is planned to accommodate tourists in some sanitariums, boarding houses and holiday homes in the Moscow suburbs," noted a fact sheet on tourism issued recently by the Olympic Organizing Committee.

"Guests will live also in campings and motels situated in picturesque spots around Moscow and the other Olympic cities (Tallinn, Minsk, Leningrad and Kiev) . . . tourists will be accommodated in comfortable students' hostels, too."

NBC has booked as many suites and deluxe rooms as possible at suitable Moscow hotels, but will not invite guests for the full two weeks of the Olympics. Instead, about 1,050 guests will be invited for stays of three or four days in shifts of 350. This way, no one will have to stay in sanitariums.

"Entertainment, frankly, is a very big problem. But considering the amount of money being spent, there are a certain number of people who expect an invite," said Jarobin Gilbert Jr., NBC's vice president for Olympic administration and the man in charge of planning the care, feeding and amusement of the corporate guests.

"The first and foremost question, as anyone familiar with Moscow knows, is, 'Once we get them here, what do we do with them?'"

The organizing committe has an answer for that, too:

"Experiences show that the tourists spend only about half their time at the sports venues. In view of this factor, tours will include sightseeing the city, visits to historical, arts and scientific museum exhibitions, meetings with colleagues, etc. Sports enthusiasts are offered visits to sports schools for children, and sports clubs and societies," the committee's tourism release states.

"The tourists will be offered river trips along the Moscow River and the Moscow-Volga Canal. The best Soviet motor boats . . . will be used for the river cruises . . . The arts program of the Games is certain to arouse as much interest as the Games themselves. About 250 best professional artistic groups from all Union Republics will show their talent during the Olympic Games."

Man does not live by ballet alone, however, and as one American resident who knows the tedium of Soviet living remarked recently, "I can hardly wait for the first time one of these advertising executives spends a day out at the "games, comes back ready for a few drinks and some action, and is told by the Soviets that the evening will be devoted to an exhibition of postage stamps."

Late night carousing is virtually non-existent in the U.S.S.R. A few Moscow hotels have "dollar bars," which accept only hard currency (no rubles) and attract their share of foreigners, but they are not likely to make anyone forget Regine's.

The ritual one must go through to bribe the doorman -- first a flat refusal to anyone without a hotel registration card, then a negotiation in a dark corner and finally payment of a dollar or two per person -- arouses great expectations, but inside there is only sightly out-of-date jukebox music and Western style drinks at $1.75 to $2.50 a pop.

NBC has anticipated all this and will, in effect, issue its invitations with a disclaimer: please don't expect breakfast at Tiffany's.

"For most of our guests, this will be a new experience, someplace they haven't been before, a life style they haven't seen," Gilbert said.

"I try to inculcate in them the idea that it will be an adventure. They will have to show more patience than they are usually called upon to demonstrate.

"There will not be five-star service. But if they accept all that and brace themselves for a little inconvenience, I think they will have an interesting and rewarding stay here."

That is entirely the proper spirit with which to visit Moscow.