When I lived up, there the "Hous"...Housatonic River...was by far my favorite to fish. It would typically fish all year, but fishing is dependent on the releases from above the special regs area. 1 generator was good, 2 was marginal, all 3 generators going meant go somewhere else. Lots of bugs in the river including midges and olives for winter fishing, and nympshs galore. It is typically open water because of the generators, even though it is a top-flow release.
I fished the Farmington mostly in Mass, but occasionally in CT. It is a good river, but I just never enjoyed it all that much.
Here's a link that has conditions for both. http://www.dryflies.com/reports-farmington.html
If it were me, I'd try to sneak away to fish the Hous @ Cornwall (go up 8,across 4, and up river rd...the "sand hole" is right on the road and a good starting point)
If you have enough time, the Deerfield and Swift rivers in MA are both bottom release and will fish well all winter. The Swift would be easier to get to for you and fishes very well with midges all winter for big browns and wild brookies.