yellowstone park-i want to camp in one place, where should I

i measured my total length. with my crew cab short box pickup, i am 47 feet long while hooked up. it specifically says "This is a single-width site. The total extended length of all vehicles and towed/towing equipment cannot exceed 40 feet." so you think i can get away with that? i dont want to reserve the sites, then get there any be screwed.....ya know? on the reservation web site they seem pretty strict about their rules