Calling and/or talking with them directly is your best bet.
TT has been around a long time and have numerous contracts within their system. Because of this information here is often correct but only partially as it only applies to certain contracts and not others.
For example: they started out selling the entire system, then at some point they went to selling regions of the county and lately they have gone to selling zones (smaller than regions). All have different rules.
AS if that wasn't bad enough they also have different levels of membership. I have never heard of one that limited where you could stay within a park. Usually it is what parks you can go to, how long you can stay, how long you might have to be out of the system between visits....
Also don't confuse Encore with TT. While both are owned by the same company they are not the same thing. If a TT member stays at an Encore park they can do so at a discount. The Encore park can determine where in the park they stay. It's not a TT rule but an Encore one (two entirely different systems).
BTW, I am not affiliated with TT in any way other than as a 10 year member. We use the parks in the Northwest about 7 - 8 months of the year. We are happy with our membership, cost, and the parks that we use. I know this can't be said for all members and that's why you need to make sure the info you get is correct. Like most things it all depends on what you want out of it and how you use it. Just because someone doesn't like the membership they have doesn't necessarily mean the entire system is bad.