Theres a sticky at the beginning of camping forum Fort Faq that lists all the loops, also theres another one for Google Earth that has overlays of the fort with all the sites and numbers. I agree about the preminum, they cost a little more but you are pretty sure you will fit. When they were redone a couple of years ago the enlarged the driveway lips for easier backing. The preferred loops 100,200,300 are still the same original size. There are some large ones but also small as well. We had one in the 300 loop one year where we could not fit a 30' 5th wheel and crew cab dually... We like the 800- 900 (pet) loops as they close to the Meadows Trading post.