I took the train east2west Chicago to Seattle once, and it went through Montana.
It was beautiful. Just stunning. The only area I ever saw that I could say would be comparable was eastern Oregon, which is as close to paradise as a man could want.
The nearest Safeway is 100 miles away, but what the hey!!
Did you nap as you drove through Idaho? The inland NW is my old stomping grounds and a place to which I will return. Eastern Oregon, Northern Idaho, and Western Montana are probably the prettiest places in the U. S. In terms of natural beauty, however, nothing compares to British Columbia, IMO.