Whatever you do. avoid Elko, NV, and the areas around Yosemite to the east. $3.49/gallon!! Way to Gouge!! 70-90 cents cheaper in Idaho and Utah.
I just went west along I-10 through Texas to enjoy that 80mph speed limit. Dunno if your car can go that fast though (ouch, sorry!) The views are great in the desert. I didn't get up to Oregon / Washington State though. Closest I made it was North Utah / Eastern Idaho. Encountered a snowstorm in Yellowstone today and part of the roads were shut down. Avoid the snow if you can! I have 2 weeks left on my trip and am threatened by snow the whole way.
Have a great trip, try to find some fun stuff to do on the way. :)