If you're heading back the way you came after your visit to CA, try to hit Antelope Canyon (Upper and Lower) by Page, AZ, and Monument Valley (AZ/UT border) - both worth a day (hire a 4x4/guide for half a day in Monument Valley)
Antelope canyon is amazing. You will fill all your storage taking photos there. Last I heard though it was difficult to get into. Monument valley was impressive as well.
Doing the tourist thing in the west completely would take a life time. So many amazing places to visit but I still like my roots in the foothills of Appalachia.