Roads within Yellowstone okay for towing travel trailer

There are five entrances to YNP but, with minor exceptions, only one road (the Grand Loop) inside YNP. Since I guess that you'll be coming from Glacier, you'll be entering the north or west gate of YNP and Fishing Bridge is on the SE corner of the Grand Loop. From either entrance its 55 miles to Fishing Bridge. Traffic is SLOW. If you need groceries you'll want to buy outside the park. Expensive, but still cheaper than inside the park.