Don't know about the eastern US but on the west coast, Thousand Trails are typically well spaced apart and in many, you can't see neighbors at all because of all the foliage and trees. But they're often old and in some of them you've got to be able to put up with low voltage, low water pressure, lack of sewer hookups, lack of 50 amps and/or overgrown trees in the way (can't be cut down or trimmed).
We don't mind being close to neighbors, but we hate it when a row of pull-through share the same pedestals and you end up with your awning almost touching theirs. RVparkreviews.com is good but note that some RV-ers expectations can very widely.