I have not studied your trip and other comments in detail but I saw that you planned a Yellowstone to Devils Tower the same time I am going. I just checked Fishing Bridge campground in Yellowstone and they are busy before Aug 15th (your date) but available after the 15th. I have driven from Canyon to Lamar Valley on the route you show but it is narrow, winding, and no guard rails. My wife freaked. Might not be good for towing a trailer. Perhaps leaving the trailer at Fishing Bridge, tour the park in the tow vehicle and leave (towing the trailer) via Canyon, Norris, Mammoth, and North out to I-90. I heard the Lamar Valley to Red Lodge route, north-east out of Yellowstone, is scenic but looks like a lot of twisties. I would like to hear from anyone who has done this route in motorhome or pulling a trailer. Charles Kauralt did it in a motorhome years ago and reported on his Sunday Morning show. In those days RVs were smaller and he had a professional driver. Do visit Lamar Valley to see herds of Bison that time of year.
