Road trip from Seattle to Park City, UT

I am taking a road trip w/ my wife and dog the end of June/July from Seattle to Park City UT to be w/ family. We are considering different routes and wanting to know any input of good locations to shoot some landscapes. Obviously there is Yellowstone/Tetons but not really wanting to battle people and since we're taking our dog we can't do much in Nat. Parks. Ideas so far are to go down from either Missoula or actually venture into Tetons, or go 84 and do Hell's Canyon. We've also been to Craters of the Moon Nat. Monument which may be worth going back since I now am shooting where before I wasn't. Ideas? We will also be car camping on the way so any good camping spots. Thanks for the input.

Should we assume you've seen Mts Rainier and St Helens? if not, why not now? Then, although out of the way, Crater Lake is awesome. Hell's Canyon is not much of a photographic opportunity, IMO. Sawtooth NRA is very scenic, and a visit to Grand Tetons is worthwhile, even if you can't leave the dog in the car for very long.