I fish the Stillwater River more than anything else. Also enjoy the Yellowstone but it is more of a nymph or streamer river. Big Horn is 90 miles away. My favorite, when I can get over there, is YellowStone Nat'l Park. The Firehole, Madison, Lamar (when fishable), Slough. Hog Heaven!
Is Clearwater Idaho over by Lolo Pass? Boy are you lucky, what a river.