I think the Parent Lifestyles Equity? owns Encore, TT, Good Sam and Camping World.
So they are related in a round-about way. I have a 2 zone pass for price of one zone .. Southwest and Northwest. just went on 6 wk oregon coast trip in july... can make res 60 days out. If you stay more than 4 nites you have to be out of the TT system for 7 days, but if you stay 4 nites or less.. can go park to park. Had a wonderful time 4 nites each of the 4 oregon coast parks, nice parks friendly & helpful staff. Am going to renew at $545 year. get 30 nites then $3/nite thereafter. Easy reservation system helpful cust service.
I have no affiliation w/TT etc. just tried it for a year and it works for me. not to say everyone will fit..
Just my 2.5 cents.