Beartooth Pass. MT 212. "The most beautiful road in America" At the south end of the pass, continue down to Cody, WY where there are superb museums of the west. Then, come back over the pass again. Alternatively, turn W at the south end of the pass and loop around the north edge of Yellowstone NP to Gardiner, MT.
Anywhere along the north slope of the Absarokas is lovely.
The Roscoe Steak House. Roscoe, MT. A half hour west of Red Lodge, MT.
Lewis and Clark Caverns (State Park) Near Whitehall, MT
Bannack State Park, a half hour west of Dillon, MT. Superb old ghost town. Two dozen buildings.