East Bloc Welcomes Visitors With Empty Arms : Tourism: The rush is on to visit Eastern Europe from all points west. Hotels, airlines and car-rental companies are scrambling to deal with the demand. For a while at least, don’t expect hassle-free holidays.

If you like rapidly evolving positive statistics, then you already love Eastern Europe. It seems that when it comes to travel and tourism figures, nearly everyone speaks in superlatives.

Boom , explosion and flood are words often used to report on the thousands of tourists flocking to Eastern Europe. To be sure, the numbers are impressive: During the first four months of this year, 4.18 million visitors from hard-currency areas (mostly Western Europe and North America) had traveled to Hungary, up a staggering 70% from the same period in 1989.

Revenues on Pam Am flights to Eastern Europe were 15 times higher in 1989 than in the previous six years. Hotel space in Warsaw and Berlin is jammed. Even charter airlines have gotten into the act.

Recently, American Trans Air commenced service to Riga, Latvia, from New York. On the ground, some countries seem to be moving faster than others. Perhaps the fastest is Hungary. By Sept. 1, three new hotels will open in Budapest, adding 900 much-needed rooms to the city.

In Bulgaria, a country generally ignored by Western tourists, officials have announced hopes to build 30 “Western-style” properties in the next five years. Government authorities are actively negotiating with Sheraton (which already manages one Bulgarian property in Sofia), Hyatt, Hilton International and Marriott.

In Czechoslovakia, 53 of the country’s newest and biggest hotels have announced that they can now be booked directly from the West, instead of via the official Cedok government service. The hotels can also be reserved in advance with U.S. dollars, instead of with the Czech koruna.

In the air, former Communist regimes are moving quickly to become truly competitive with the West: They are ordering U.S.-made planes and upgrading service.

Malev, the Hungarian airline, has plans to replace its entire fleet of 21 Soviet-built jets with U.S. airplanes. LOT, the Polish airline, is now using some Boeing equipment. (None of the airlines has started a frequent flier program . . . yet.)

Now that the Communist world has embraced capitalism, it seems that every airline, hotel group, rental-car company and tour operator wants to return the gesture.

Already, many airlines, including U.S. carriers, have either applied for new routes to Eastern Europe or have increased service there.

Hotel companies have announced new construction or management contracts to run existing hotels. For example, Sheraton, Hyatt, Marriott, Ramada and Pullman hotels have announced plans to build new hotels in such cities as Warsaw, Belgrade and Moscow.

And tour operators are now offering tours to previously inaccessible destinations, or places that had been severely limited to tourists.

The barriers have indeed come down. But what will travelers find behind the doors?

As euphoria begins to settle into the reality of continuing economic despair for most of these countries, there are a few things you should know before booking your trip East.

Since tourism is so dependent on service, the development of Eastern European tourism starts with two strikes against it.

“People were downright giddy with joy,” says one hotelier in Germany. “But the problem comes with their expectations.”

Before the Berlin Wall came crashing down, many U.S. travel concerns--hotels, tour operators and airlines--were already operating in countries such as Poland, Hungary and the Soviet Union.

Still, a number of corporations were complaining about the difficulties of doing business in the Eastern Bloc. Officials of InterContinental Hotels met privately to discuss pulling out of some Eastern European cities.

“It was getting impossible to maintain our style of service there,” reports one general manager who attended the high-level meetings. “We couldn’t get supplies that our international guests had come to expect, and worse, we couldn’t get such basic services as water, natural gas and electricity on a consistent basis.”

Just when InterContinental was getting ready to pull the plug on some of its hotels, the Berlin Wall came down and, suddenly, the rush was on for Eastern Europe.

In some cases, even when light appeared at the end of the tunnel, it seemed the tunnel kept getting longer. For example, the Soviets opened a luxury hotel in Moscow (the Savoy, formerly the Berlin Hotel) as a joint venture with a Finnish company.

The newly renovated hotel boasted room service, a bar with cable TV and Moscow’s first approved casino (restricted to holders of a foreign passport or Western credit card). That’s the good news.

Now, try to get a room there. The hotel is booked--for the next five years solid--by Finnair for its clients.

Another continuing problem with traveling to Eastern Europe is in the area of rental cars and the hassle of fuel compatibility. As a number of tourists discovered recently, it is virtually impossible (with the exception of Hungary) to find unleaded gas in Eastern Bloc countries.

But almost every car rented in Western Europe takes unleaded fuel only. As a result, a number of unsuspecting travelers rented cars in France and West Germany, only to run out of gas in Eastern Europe. They had to abandon their cars there. Not surprisingly, retrieving the cars was a costly experience both for the companies and the renters.

Thus, at least for the time being, if you plan on renting a car for a trip through Eastern Europe, it might be a better idea to wait until you get there. For example, Budget Rent-A-Car has offices in Hungary, Czechoslovakia, Poland and Yugoslavia, and the company guarantees its rates in U.S. dollars.

Europcar (the National Car Rental affiliate in Europe) has opened offices in East Berlin and Leipzig. You can also find Europcar outlets in Yugoslavia, Poland, Hungary and Romania.

But before you rush over to Eastern Europe, you need to face some facts:

--Hotel space is tight. Polish officials estimate that Warsaw will need 3,000 more hotel beds every night from now through the end of September. Prague has a similar problem.

--Even if you can get a room, expect to pay for it. Already, the East Germans have raised hotel room rates as much as 50% over 1989. And don’t expect all the usual amenities. First, most Eastern European hotel rooms are not well-designed. Don’t always expect hot water or consistent electrical current. And, sometimes, don’t even expect soap.

--Think ahead. Bring an extra roll of toilet paper, your own washcloth and extra soap. If, like me, you get spoiled and frequently use hotel-supplied shampoo when traveling, don’t be surprised if those kinds of products are not in your bathroom when you arrive.

--Finally, don’t go anywhere in Eastern Europe without a confirmed reservation . . . in writing.