36 ft FW vs 30 ft TT backing

I agree with the other posters. The trailers back differently, but each has its own advantages and disadvantages over the other. Barring obstacles such as trees, posts, signs, culverts, etc., next to the campground road and/or adjacent to the campsite driveway, I think I could put either one into the spot with a little time and patience. We have a 35' conventional travel trailer towed by a crew cab truck, and run into such problems when we decide to go camping with little notice, and the campgrounds are too full to be able to choose the best spots for our rig (mainly in nearby U.S. Army C.O.E parks at local lakes). Only occasionally are we not able to get the trailer in due to its length and the maneuverability of the combination, usually in spots which are really too short for the truck/trailer combination to park in when hitched together anyway. Most Corps gatekeepers are willing to let you try, but if you are dealing with a privately owned campground that's had bad experiences with that site in the past, they may not.

Even though you said sharp turn was the issue, I'd also be aware of the height difference from most TT and 5th wheels ;)

95% chance if the 30' TT fits, so will the 36' 5th wheel.

They back slightly different but if you know what you are doing, you can get them into roughly the same positions.

Since a FW is slower to react to truck movement, you often times have to pull farther past your site, before backing. If there is an obstruction in the way by pulling farther ahead, this may be their reason. IMO, if you can get that length TT in there, your FW will fit also, but may require a little more back/forth, and patience.

Jerry

Someone who is skilled can back either into spots most would consider too tight. I would suspect they are remembering problems some folks have had with getting into a spot and are playing it safe. I doubt they would turn down a potential paying customer without have a legitimate concern.