We decided to start our return trip west to Portland by heading due east over the Beartooth Highway. This drive is absolutely spectacular and you really must include it in any trip you take to Yellowstone. It is one of our favorite drives in the US. A lot of better writers than I have described it so I am going to pass. All I can say is make sure you do it at least once.
After coming down from the Beartooth we jumped on the interstate and headed west towards Bozeman. The place we had picked out to stay was full, so we continued heading down the interstate until we came to Three Forks where we ended up in a commercial campground.