Trailer length - does that influence spot availability?

There’s not really a magic number on length. I’ve seen max length vary by a foot site by site in the same campground at a state park. I had to shrink my camper by a foot to get a site.

Also I’ve seen the sizes not be accurate on websites. A Corps campground had a site listed as 25’ max, but I was pretty sure it was longer from the picture, so I called, and it was longer. It could have handled a 60’ trailer and a couple of trucks.