I don't think such a route exists. You might be able to get as far as the Quabbin without too many extreme hills, but getting past the reservoir and then climbing out of the CT River valley is one tough ride.
I've done a NY-CT ride swinging south of the Quabbin, and also a loop between Worcester and the CT River on the north side, and it's pretty gruelling either way.
The whole Valley seems to have some kind of hex on it for me, too- anything that can go wrong with a bike WILL happen to me in that valley. On the plus side, the locals were consistently very nice, and on two occasions gave me 15-20 mile lifts to the nearest town with a bike shop.
As far as an easy route goes, I've yet to find a good one, but it's definitely worth the struggle once you get into the mountains.