Don't discount the convenience factor associated with the ACA maps, especially if you are sort of person who likes to know where he is going to stay and eat every night.

Also, east of Missoula you have only one hard mountain pass--Lost Trail & Chief Joseph Passes (three miles apart). The next two--Big Hole and Badger---are not bad. You will hardly even know you are climbing Big Hole until the last 3 miles.