Every loop will be near a comfort station...there many. Check out the map on one of the other threads and look for the CS signs on the map.
The pet loops are 300, 700, 800, 1600-1900. And then there are the overflow pet loops: 500 and 600.
You can request a non-pet loop, but we did not find a lot of pets there during December...
I didn't believe folks when they said that it's fun to take pot luck, but Fort Wilderness is such a cut above any other campground we've been to, you'll love whereever you are. (Well, except for 1900. I found it too quiet and dark for me...almost spooky.)