Interesting how Mormonism came out of the same area at the same time. Were any other religions or cults part of that tent revivalism culture? I thought JW's but that's further south and a few decades later.
The colonies are definitely a good place to visit. Tho' you have to travel a bit further and look carefully to begin to pierce the veil they put up for outsiders. Even then, you are still an outsider.
As for the Amish, they're here in NY. Not what you would think. A good start is Amish Society, by Hostetler.