1000 Trails really makes sense when you fulltime. But buy your membership on the resale market - you ought to be able to find a good nationwide all-parks plan for around $2500, and you'll also be able to access the Encore parks at a discount. We tend to spend about half our year in 1000 Trails parks - so far this year we're planned out thru September with 177 1000 Trails nights booked.
Encore parks tend to be spendier than we like, but sometimes they are the best (or only) game in town, so we use them sparingly. All depends on where you want to go.
There are divisions within 1000 Trails - 1000 Trails, Naco, Outdoor World and Leisure Time. Make sure you get access to all of them.
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