I mostly make heaps of composite cassettes from my collection, but if I had a CD player in the car, I'd definitely take these:

Terry Allen - Lubbock on Everything & Smoking the Dummy
David Mallett - Inches and Miles
Mark Germino - Caught in the act of being ourselves
Kate Wolf - Gold in California
Koerner, Ray and Glover - all 3 CDs on Red House
Suzy Bogguss - Somewhere Between
James McMurtry - Too long in the wasteland
Bob Neuwirth - Back to the front
Billy Joe Shaver - Old five and dimers like me
Robin and Linda Williams - Close as we can get/9 'til midnight
John Prine - Great days anthology
Richard Thompson - Watching in the Dark anthology
Cassell Webb - Songs of a stranger
Tish Hinojosa - Homeland

Regards, Stewie