Wondering if anyone can help on actual size of a camping spot I need to reserve for a popup at Yellowstone sites? I have a Jayco Eagle 10 foot box w/queen on one side and a twin on the other pulled by probably a 15 ft Yukon. I have two nights reserved now in Canyon in a 30 foot or less. All 40 foot sites are all reserved at this point. Is there any wiggle room on these sites? Can't imagine that 40 foot sites would be only ones that could accommodate basically a medium sized popup? Also, have plans to move on to another non-reservable site we can nab later, think this will be hard to do around June 24? This will be our first camping trip to Yellowstone, although was there 20 years ago on a day trip.