across to Whitehall and then across via 287 and Ennis/West Yellowstone. These other stretches were all reasonable roads and Boulder/Whitehall was a nice out of the way ride.
Did you take MT 2 from Whitehall to 287?
Two years ago I rode from Ennis to Lewis & Clark Caverns State Park via 287 and MT 2 then through Whitehall to Butte. The crosswind on 287 was intense. Stopped to take my sleeping bag off the front rack and put it in s pannier. That turned into a headwind when I turned west onto MT 2.