Some of the sites have trees and other obstacles. I normally stay in a site that says trailer length 18 but I comfortably put my 24' trailer and truck on the pad with no issues. That is this one specific site though, it does not apply to all of them. You need to see if your trailer will fit. If you get there and your trailer does not fit it will be your fault as they said 18ft.
I saw someone complaining that their equipment did not fit. They cited the length listed on the campsite details and told the people too bad.
Do a little research before you try and stuff your trailer in.
Which site do you have and what is the length of your equipment, I will take a look if I make it up there before you go.