THE WISE traveler, no matter how experienced, always welcomes helpful information from authoritative sources--especially when it's free. Besides answering specific questions, state travel offices and area visitors bureaus often provide guides, maps, calendars of events and other helpful publications. Here are a few that are currently being offered by mail:

* New Mexico recently completed its first major revision of the official state road map since 1972. The attractive and practical Travel Map of New Mexico, with a full-color cover photo of the Organ Mountains in the southern part of the state, includes a guide to camping and recreation areas. Issued by the New Mexico State Highway Department and Commerce and Industry Department, it's available by writing to the Tourism & Travel Division C&ID, Room 751, Bataan Memorial Bldg., Santa Fe, N.M. 87503, or call toll-free (800-545-2040).

* Ocean City, N.J., has a 50-page, full-color Vacation Guide to the resort. Write Ocean City Vacations, 1300 Ocean Ave., Ocean City, N.J. 08226, or phone their new toll-free number (800-225-0252) between 10 a.m. and 6 p.m.

Arizona's bright, 82-page Visitors Guide covers everything from essential facts, services and attractions to day trips, accommodations and transportation. In color. Contact the Phoenix and Valley of the Sun Convention and Visitors Bureau, "The Park," 4455 E. Camelback Rd., Building D, Suite 146, Phoenix 85018 (602-952-8687). Incidentally, the Bureau also has a toll-free number (800-528-6149), which cannot be used to order the guide but does provide one-call reservation service for more than 100 hotels and resorts in metropolitan Phoenix and the Grand Canyon National Park lodges, plus reservations for car rentals, condos, bus tours, air tours and even--for the adventurous--those unforgettable mule rides into the Canyon.

* North Carolina's new edition of its Camping and Outdoors Directory is a very useful 68-page booklet about the state's parks, recreation areas, small state forests and national forests. Copies from the Travel and Tourism Division, 430 North Salisbury St., Raleigh, N.C. 27611 (919-733-4171).

Delaware offers a convenient Calendar of Events listing the state's special events through October and permanent attractions. From the Delaware State Travel Service, 99 Kings Highway, P.O. Box 1401, Dover, Del. 19903 (toll-free 800-441-8846).

* Lancaster County, Pennsylvania, says "Come Home to Pennsylvania Dutch Country!" on the covers of a travel brochure and its new full-color, 32- by 22-inch Map and Visitor's Guide, which is designed to permit easy location of attractions, restaurants, shops and lodging. Copies, and a reduced admission pass for the area's introductory movie plus information on events, from Pennsylvania Dutch Visitors Bureau, Dept. 2014, 1799 Hempstead Rd., Lancaster, Pa. 17601 (800-55-DUTCH).

* Philadelphia's 40-page 1983 Official Visitors Guide, complete with maps of Center City and the region, includes history, hotels (even B&Bs), food and attractions. It's informative, easy to use. From the Philadelphia Convention and Visitors Bureau, 1525 John F. Kennedy Blvd., Philadelphia, Pa. 19102 (800-241-8444).

FLORIDA FERVOR: Sea World, Inc. at Orlando, aware that Disney World's Epcot has had a dramatic impact on central Florida tourism, notes that many vacationers have been buying Disney's three-day pass and then trying to squeeze the numerous other attractions and side-trips into what's left of a one-week holiday. This concerns Sea World because many potential visitors to its six major show areas don't have the necessary six-hour block of time in a single day and are bypassing that attraction.

So Sea World has come up with a "Week-Long Pass" that costs $15 for adults, and $14 for children 3 to 11--only $3 more than regular one-day admission--and permits unlimited visits for a week with discounts on food and merchandise.

Meanwhile, Florida Cypress Gardens at Winter Haven, a major tourist draw for more than 40 years and still competing, is preparing to unveil a new attraction, "Island in the Sky," in September.

Sponsored by the Eastman Kodak Co., the $2 million landscaped tropical "island" surrounded by water is really a revolving platform which will lift 100 visitors--many of them presumably holding cameras--150 feet above the Gardens. They will get a 360-degree panoramic view of the flowers and unusual angles for snapping shots of the water skiing shows. The park doubled its size only three years ago.

PROJECT OCEANOLOGY: If you've ever wanted to haul in a trawl net and examine the catch, learn how to use oceanographic instruments or see microscopic plankton, board the 50-foot Enviro-lab in Groton, Conn., and take a 2 1/2-hour cruise, rain or shine.

Operated by a nonprofit association of public and private schools and colleges, Project Oceanology is a marine education center whose objective is "to foster an appreciation of our relationship to the marine environment." Now celebrating its 10th year, it provides boats, oceanographic equipment, laboratory and staff to annually give more than 10,000 students and adults first-hand experience.

The vessel can carry 48 passengers and embarks Saturday, Sunday, Monday and Wednesday from the dock at the USS Croaker Submarine Memorial on Thames Street in Groton. Cruises continue through Sept. 5.

Tickets, sold at the Memorial, are $8 for adults, $6 for children under 12. Reservations suggested (203-448-1616).

LOBBY LIBRARY: When the $70 million, 534-room Waverly, a Stauffer Hotel, recently opened in Atlanta, guests quickly discovered one of the reasons general manager John R. LaBruzzo compares a stay there to being "a welcomed guest in a rich man's home." Among the Waverly's amenities is one that's unusual for hotels: a 4,000-volume library.

The library is just off the lobby, and fiction, nonfiction and reference books line mahogany-paneled walls in wooden bookcases. There are also current magazines and newspapers. The 15-by-15-foot library has a fireplace with gas jet and is furnished with high-back Queen Anne chairs, a fine wooden table and European antiques.

LINDBLAD CELEBRATES: Lindblad Travel Inc., a tour operator well-known for pioneering trips to unusual far-away places, is observing its 25th anniversary and the 15th anniversary of the M.S. Lindblad Explorer's first cruise to South Polar waters. President Lars-Eric Lindblad and his wife will mark both occasions by hosting an Antarctic expedition on Nov. 15.

"Nineteen years ago," Lindblad recalls, "I took the first group of adventure travelers to visit Antarctica. We used the Argentine naval transport, Ara Lapataia, and brought 56 people to this remarkable 'frozen continent.' It was a historic event and one that I've repeated every year since 1965." Lindblad launched his own vessel, the 92-passenger Explorer, in 1969.

Members of the tour group will fly to Buenos Aires, then continue on to Montevideo where they will embark on the Explorer. Ports of call on the 30-day journey include the Falkland Islands, South Georgia, the Orkney Islands and the Antarctic Peninsula. Passengers disembark in Punta Arenas, Chile, and fly home via Santiago.

Cost of the expedition begins at $7,200 per person, double occupancy. Air fare is extra. Further information or brochure from Lindblad Travel, P.O. Box 912, 8 Wright St., Westport, Conn. 06881 (203-226-8631).