In the winter there's standing water on the Bonneville Salt Flats, I wonder how high a person would float in that. You aren't heading up to Butte then through Missoula and Spokane? We liked what we saw of Missoula at Christmas. If you get fuel in Dubois I'll be amused.

Any chance of swinging through Yellowstone? I think the hot springs there are rather too warm for swimming though.