I'm late to the party here, but.......... Stayed at Fishing Bridge. Too cramped and if the stumps at the back of the site are too high you will be limited to how far you can back up. When you cross the stumps you are also right in the space behind you. Not a good situation.
Bridge Bay we have stayed in as well. There you can get into a turn out type space rather than a back in. we are 40' with 4 slides and we do not stick out too far to cause problems. Its dry camping but really fun. Lots of wildlife. So we are done with FB and will only go to BB. Bridge Bay is also a very central location to work all areas of YNP.