We drove over Beartooth Pass several years ago, from Red Barn into the eastern end of Yellowstone, towing our 27. First, it was stunningly beautiful, and second we did not have any issues towing. You do cross at about 10,000 feet elevation, but it was perhaps the favorite part of our trip to Yellowstone.
2008 Airstream 27FB International Ocean Breeze
2014 Ford F250 King Ranch 4X4 w/6.7L Diesel, Hensley Hitch