I just Googled Information on Bryce Campgrounds and North Campground and Sunset Campground appeared on the list. If you click on North Campground, then click on the Reserve America link, then Site List, you'll see that there are at least a couple of pull through sites that are 50' in length. Here's the
link. I did the same for Sunset, but the Site List does not list length. Sometimes you have to click on a site, then open it for detailed information and it will list the length. Good luck.
The other thing would be to use Google Maps and enter in the campground name, then using the length measurement on the bottom of the screen, determine the length of RV's you can see in the photo. Problem here would be the trees. Trees may not allow you to accurately see the sites from above. Worth a try though.
2011 Bighorn 3055RL, 2011 F350 DRW 6.7L 4x4 Diesel Lariat and Hensley TrailerSaver BD3, 1992 Jeep ZJ and 1978 Coleman Concord Pop-Up for remote camping
Dave & Renee plus (Champ, Molly, Paris, Missy, and Maggie in spirit), Mica, Mabel, and Melton