The cell phone and AAA membership isn't a bad first option, but out here in the Pacific Northwest some amazing roads with not-to-be-missed curves and scenery are in areas with no cell service. You could easily find yourself a half day walk from a landline, too. So pack your choice of tools, spares, and water. Plan your gas stops and let someone know roughly where you're going (I know, we like to just go with no plan...guilty). Also remember this, the real first line of defense against breakdowns is maintenance.