Possible Clues:

• Cal.-to-Fla. highway
• Fla.-to-Cal. highway
• Major Calif.-to-Fla. route
• Cal.-to.Fla. highway
• Rte. through Houston
• Major Calif.-to-Fla. hwy
• Calif.-to-Fla. hwy
• L.A.-to-Jacksonville route
• Coast-to-coast hwy
• Santa Monica-to-Jacksonville rte.