Folks really should mention about the curves on US 12.
Drove it last fall, from Missoula to Lewiston. Scenic, I think. :h
That's because the whole route is nothing more than one endless curve.
You come out of one, you can see the next one already, and maybe even the one after that.
Scenic, yes it probably is, but as a driver, you're not going to see it.
Passengers will love it, they can actually look around. Driving, not a chance, you've got to watch for that next curve you're almost into again.
I got so tired of it after awhile I couldn't wait to get off it.
Mind you, there are plenty of spots to pull over alongside the river or other places to take a break, and enjoy the gorgeous scenery.
But I surely did not enjoy the road.