TT can work well for some. It depends upon the parks that are in the regions you want to explore. As mentioned, some parks were rather 'distressed' from a combination of neglected maintenance, and IMO - overselling of the number of members using the available sites. We have a close family friend that took over her Mother's long term TT membership. Three of the parks they frequent the most, all happen to be in California, have over the last 5 or so years, started to have funds pumped back into maintain them. Heavy infrastructure repairs first, then cosmetic repairs and rebuilding of aged buildings and restrooms and pools, etc. And some have expanded and added more cabin spaces for rent.
The key, is getting one of the old grandfathered plans, that allows the furthest out reservations - in popular TT's, if you do not have one of the older plans with the ability to make reservations out ahead of the pack of the new planned members - well, it's a crap shoot to get a reservation
!
Financially, if the parks are in a location that you will use them, it can pencil out to be a good bargain.
One thing I've seen some people do. Is sign up for the sort of 'pay as you go' regional plans, in areas that they want to check out. And get a feel for the parks themselves. Some people don't like TT's because they usually have packs of kids being kids (Having a blast! And that naturally can equate to loud voices and laughter and, etc. behavior!). As I recall, these regional type plans are something you can walk away from(?). But, you can also check out the parks, and see if you want to invest in buying a plan from someone. (Two people we knew, had to do this in the off season's, because they could not make reservations.).
We have not done TT. We've found that we seem to 'fit' in better with Escapee's Parks in the places we travel. We do visit TT as guests of the family friend, usually in the Yosemite and Tahoe areas, when multiple family members and friends all meet together every other year. But, that's just us, and we do boon dock and National/State/BLM/COE parks quite a bit - so we do not go 'park to park'.
Best of luck on your research,
Smitty