Hiway 2 across N.D. and Montana is absolutely nothing. Also It looks like you're not going to Rushmore, Yellowstone, Glacier... Good stuff. Hiway 2 is great across Washington. Also hiway 12 from Missoula over Lolo pass. The Columbia River Gorge is best seen from the Washington side, if you come south. i just got back from a 6 K ride in Oregon and California. On your way back Northern Cali hiways 36, 3, 299, 96, and 1 are great. Plan a route thru Tahoe, Yosemite, Kings Canyon, and Seqoia national parks. The valley is hot and the coast doesn't often have good weather.
Rubber side down...
Don
Feed the addiction...