The following link has a good image showing the different geological areas (but not roads) in Eastern Washington:

http://www.bentler.us/eastern-washin...state-map.aspx

I actually live in southeast Washington and have driven through these areas but only done a little photography in the Cheney-Palouse scablands, which are relatively close to my home. The Mountaineers have published a 100 Hikes in Central Washington book (or something like that) that covers a lot of these areas.