My room mate Tim is going on a two week trek out west. It sounds very busy but alot of fun. Last summer I made it out West on a nice road trip. Paul and I spent time in Glacier National Park up in Montana, spent a weekend on the Oregon coast visiting my brother, and drove through Yellowstone. The Oregon coast is very cool. There are some very interesting areas along the coast.
The Rockies are awesome. It is so different to drive around them compared to anything out East or in the Mid-West. I haven't been to the Grand Canyon or Salt Lake so I can't comment on how they shape up. I would be willing to bet they are very interesting interesting.