If you're going through Arizona, you may well be going on Route 66 (as it used to be) at some point, in which case the Rolling Stones spring to mind. In Winslow Arizona you'll find a "Standing on the Corner" park, named after the Eagles song (and in fact the Eagles would be good road trip music - Hotel California?) Some Joni Mitchell from the first four or five albums maybe? Ladies of the Canyon?

Jenny