This is, to me, the single biggest draw back of owning a fifth wheel - clearance!
I've stayed at some very high end RV resorts (Cedar Point in Sandusky, OH comes to mind) which cater to high end motorhomes and fifth wheels, yet have many low hanging trees and sharp branches. Many attempts to have them address this have gone unanswered.
State parks in Michigan also tend to have many low branches. There are entire sections of campgrounds that I can't even go into, with branches as low as 9' (I know this because I can jump and touch them).
Shortly after buying the Big Horn, I bought a 14' extendable tree lopper/pruner that I carry in the basement of my RV, just in case.
I've used it before, and will use it again if I need to. My feeling is that if you are renting me an expensive spot specifically deemed "Big Rig Friendly" then you have a responsibility to make sure my big rig can get in there.
I have a lot of anxiety going to new campgrounds where I don't know what to expect. One of these days I'm going to get in a jam and won't be able to turn around or go through due to tree limbs. This keeps me awake at night.