I would recommend NOT doing the patch, especially for just driving. I'd do bonine. The patch left me woozy and hung over, with no booze involved.
You are going to be driving, but not stop and go, and not a lot of curves (maybe some in yellowstone). As has been said, it is drop dead glorious scenery, and unrivalled anywhere in the world. Go and enjoy.
The heat will not even feel like that temp--it is very dry. Don't forget your sunscreen and a lot of water.
For your motion sickness, have some saltines available also.