IF YOU'VE HAD problems getting a room for the 1982 World's Fair at Knoxville, or are now ready to make your reservations, you'll find the phone number is the same: (615) 971-1000. But there's been a shakeup at the other end of the line that officials hope will result in better service.

Members of the Greater Knoxville Hotel and Motel Association, however, contend the change will hurt their business. They are setting up a same-day room referral service for visitors who arrive without a reservation. The phone number will be available at welcome centers and elsewhere within a 100-mile radius.

Irate Washington-area residents have complained of delays in processing reservations, not getting the property they had selected, paying $65 a night for "roach-infested rooms" and being booked into a motel "not yet built." Some visitors said they were assigned accommodations many miles from the fair site only to discover later that better rooms were available nearby.

The corporation running the Fair (Knoxville International Energy Exposition, Inc.--KIEE) first named Knoxvisit as the official organization to handle hotel-motel reservations, in addition to its regular job of supervising the city's convention and visitors bureau. Recently, KIEE replaced Knoxvisit with PLM/Hotel-Motel Division, Inc., a division of the R.M. Moore Co., a real estate firm in Knoxville.

"There have been some problems and we're doing our best to work them out before the peak tourist season hits in mid-June," says the official spokesman for the fair. He denies, however, that the change in the reservation system was prompted by complaints, explaining that "there were some foul-ups but the system was to blame." Knoxvisit originally "was not set up to handle hotel operations on a day-to-day basis," he says, and the staff is now devoting full time to the visitors bureau.

"Most people are having a good experience--some obviously are not and that's regrettable."

Returning visitors also warn, based on what they saw happening to others in Knoxville and Gatlinburg, not to go to the fair unless you have written confirmation of your hotel reservation--or at least a reservation number from the official housing authority.

The Knoxville official agrees with the warning. He notes, however, that it is possible to arrive in Knoxville or one of the surrounding towns without a reservation and still find a room, although there's no guarantee you'll find what you want on the day you need it.

The World's Fair, which has been drawing between 60,000 to 70,000 visitors a day, runs through Oct. 31.

The hotel and motel association is upset, says Lin Courtenay, association president and manager of a Quality Inn near the Knoxville airport, because it fears that since PLM is owned by a real estate agency, "they will be interested in channeling tourists into supplementary housing: non-hotel/motel accommodations like bed and breakfasts, condos, apartments and houseboats . . . things the customers are not looking for."

Courtenay says rents being charged for those properties are not cheaper than many motel rooms, and in some cases are higher. His association was scheduled to meet last week with PLM officials. In reply, Reggie Castle, president of PLM, says his company handles only hotel and motel reservations for the fair. He says he is ready to meet with Courtenay and discuss the association's problem.

Amtrak is convinced there will be no beef about its prime rib.

One of its most popular dinner entrees, its 10-ounce boneless Prime Rib, has returned to the menus of all Amtrak's long-distance dining cars. It had disappeared last October when Amtrak was ordered by Congress to cut losses (which had been running about $60 million a year) in half.

Taking what a spokesman described as "drastic steps," the company stopped all food preparation on its trains. Tray meals were bought forzen from vendors, were heated in infra-red ovens, and served airline-style with plastic utensils.

"We received complaints, particularly from older passengers and regular train riders," the spokesman explains, "so we began experimenting on what we could do to restore some of the niceties without increasing cost. Earlier this year we began serving freshly cooked breakfast--it's not as elaborate as before, but you can order fresh eggs, bacon, ham and toast." Also restored was a tablecloth (these days a paper one), a pitcher of water, salt and pepper shakers and a vase of artificial flowers on each table.

Amtrak will continue to add "whatever amenities we can without increasing cost."

The U.S. State Department has "strongly" recommended that Americans not visit Ghana "except for essential reasons." It reports that "a number of foreigners, including U.S. citizens, have been detained without warrant and without notification to the arrested individual's embassy . . . In addition, travelers arriving and departing Kotoka International Airport in Accra have been subject to body searches and private correspondence has been opened."

State's advisory says there's a curfew from 10 p.m. until 5 a.m., it's difficult to arrange hotel accommodations, food and gasoline are in short supply and prices are high. It advises Americans who do plan to go the Ghana to notify the embassy there both before and after their arrival.

Are you waiting to take your vacation on the last of the big ocean liners, the Queen Elizabeth 2?

Cunard officials have been even more anxious. Last week they were nervously watching the conflict in the Falklands and hoping for an early peace--their luxurious flagship, stripped and refitted, has been hauling grim British troops to the combat zone instead of carrying happy passengers on cruises.

A Cunard spokewoman said it would take "four to six weeks" to refurbish the vessel for pleasure travel after the British government returns her to the company. The next Caribbean cruise is not scheduled until November, but transatlantic and Canadian cruises are being cancelled while the big liner is on war duty. Cunard is accepting bookings for future cruises on the QE2, while its other ships, the Countess and the Princess, are still in service in the Caribbean.

The P&O's liner Canberra was also seeing duty in the Falklands after being pulled out of the Mediterranean. She'll receive "a very thorough refitting" after the war ends before being returned to cruising, according to the line.

Most weather buffs are familiar with NOAA, the Commerce Department's National Oceanic and Atmospheric Administration, through its regular Weather Radio broadcasts that may include travel and recreation forecasts. But NOAA also offers a number of free publications that can help seaside vacation planning.

Like to know the "biweekly average water temperature from April through October" for 35 areas, or what months are best for fishing, swimming or boating and how many days of good weather you can expect at San Francisco Bay, western Michigan shore, Lake Erie, Lake Ontario, southern New Jersey, North Carolina, coastal Mississippi and the Delaware Coast? For "Water Temperature Guide to Atlantic Beaches," write Resort Guides, National Oceanographic Data Center, NOAA, Washington 20235.

Brochures on marine and estuarine sanctuaries are available from NOAA's Sanctuary Programs, Office of Coastal Zone Management, same Washington zip.

No one wants to think about hurricanes on a vacation, but NOAA points out that the big blow "can threaten any area of the nation's Atlantic or Gulf coasts during the late summer months." For facts on the frequency of severe storms, write Office of Sea Grant, NOAA, Rockville, Md. 20852.