FW can handle the largest RVs. There are some sites that are better than others for big rigs. However, the current tree trimming is aimed at making most or all full hook up sites suitable for all RVs. FW will NOT put you in the parking lot. In fact they absolutely forbid camping in the parking lot. I have been at the front desk when a person in a Class A was instructed that they must leave the property because they showed up a day early and there was no sites available for that day.
If the thread you read was mine on parking lot changes I am sorry for the confusion. FW does not put make the RV stay in the parking lot. They just make the RV leave their boat, car, utility, or golf cart trailer in the parking lot. In the past FW had let people put these type small trailers off to the side of their site in the grass. Well, you were never supposed to do that but they were not enforcing the policy. Now they are.