There are a few things you should know before trying to drive in Mexico:

*If you plan to drive more than 60 miles south of the border or to stay in Baja more than three days, you must get a Mexican Tourist Card. You'll need proof of U.S. citizenship: a passport, birth certificate, military ID card or voter registration card. The tourist card is free and can be obtained at Mexican consulates, at the border or at the Mexican National Tourist Council or Travel Department offices in major cities. (A permit is also required for boats and trailers, for which you must provide proof of ownership at the border.)

*U.S. automobile insurance is not valid in Mexico, and every vehicle must have a Mexican insurance policy that also covers any boat or trailer being hauled. Check with your insurance carrier for details or check with Instant Mexico Auto Insurance in San Ysidro, Calif.

*In the more remote areas of Baja off the main paved roads gas stations are few and far between, so carry some spare gas. And once out of border towns you should have pesos to buy gasoline since dollars are not always accepted.

*If you venture into remote areas, take along extra water and food in case your vehicle breaks down.

*Park entrance fees are not fixed, and visitors are asked to give what they think appropriate. We paid $4 a car.

GETTING THERE: If you don't want to drive, there are flights from Seattle, Tucson, San Francisco and Los Angeles to the cities of Loreto, La Paz and San Lucas on either Mexicana or Aeromexico Airlines.

TOURS: Several tour organizers offer a variety of expeditions to Baja, among them: The Sierra Club, 530 Bush St., San Francisco, Calif. 94108, (415) 981-8634. The National Outdoor Leadership School, Box AA, Lander, Wyo. 82520, (307) 332-6973. Sobek Expeditions, Angels Camp, Calif. 95222, (209) 736-4524.

For additional outfitters, consult one of the many adventure travel catalogs available in book stores or contact the Mexican National Tourist Council.

WHAT TO DO: In addition to snorkeling, diving and surfing, the waters off Baja offer excellent fishing. The supply of marlin, tuna and sailfish has attracted sportsfishermen to Baja for years, and there are scores of big game fishing trips arranged by hotels, the airlines and travel agencies. For more information, contact the Mexican Department of Fisheries, 1010 2nd Ave., No. 1605, San Diego, Calif. 92101.

INFORMATION: The Mexican National Tourist Council, 10100 Santa Monica Blvd., Los Angeles, Calif. 90067, (213) 203-8151. Or try the Mexican Department of Tourism: Call 011-52-682-21190 for information on Baja California Sur, 011-52-668-23347 for the northern state of Baja California. The State Tourism Office also has two numbers: 011-52-682-21199 for Baja California Sur and 011-52-668-842126 for Baja California.