I always thought the mill in Carolina, RI was long gone, but when you drive by you can see some buildings there, so I checked it out. Turns out there is a ton of really neat stuff! It is all privately owned, but very cool. There are quite a few buildings that are still upkept, and a bunch of neat machinery and the like. If I ever get to check it out with the owner I'll post a bunch of pics. For now here's a little of what I saw:
This house on the property was built in 1770
Some machines on the property
Interesting old machine
A neat part of the original stone mill
A final overview with the large brick building in back, waiting to be explored!