Rainbow Reservoir is a section of the Farmington River that lies below the Rainbow Dam in Windsor CT. It is a 234 acre reservoir, is entirely tree-lined on one side (Northwest park in Windsor is on this side). There are a few houses on the other side. For the most part it is very quiet, but power boats occasionally make an appearance. My last time there, some younger folks put a ski boat in and that sort of ruined it. If it weren't for that, I would have had the entire place to myself except for a couple of fisherman in a boat with an electric motor. I have been there a few times now, and can paddle the entire length and width of the reservoir in about 2.5 hours. It is very enjoyable, and there is a good boat launch there.
I don't think there are. There was no one there to pay a fee to.
In Windsor, take Rte. 75 N. Go west on Rainbow Rd. Take a left on Merriman Rd and watch for boat launch signs on left.
Very wide concrete boat launch. Large parking area. Quick to get to if you live locally.