A good resource for Baja travelers is "Mexico's Baja California" book (Automobile Club of Southern California, $18.95), which charts the Transpeninsular Highway mile by mile. Here are a few tips from David Brackney, the author of the book:
If you're staying more than 72 hours — or traveling south of Ensenada — you need a tourist card. They're available at the Mexican customs office at the San Ysidro-Tijuana border.
Buy gas when you can. It often sells out in small towns along the route.
Be courteous when stopped by soldiers at highway checkpoints. Sometimes they'll wave you through, but often they'll search the car for drugs and weapons.
Allow yourself enough time to travel more slowly than you would in the U.S. "It's not I-5," says Brackney. He recommends taking four days to drive Route 1 one-way from Tijuana to Los Cabos.
Special auto insurance is available from agencies such as the Automobile Assn. or at storefront offices near the border for less than $20 a day.