I did a tour from New Haven to Montreal in Sept-Oct 2007. I used Route 5 from Brattleboro VT to White River Jct VT (where I turned westward towards Montpelier). Route 5 was pretty decent there. Shoulder was ok for most of it, traffic was moderate, and there were some rolling hills, but nothing super-bad. You get to go through some pretty towns like the above-mentioned plus Bellows Falls. There's also a Harpoon Brewery outside of Windsor, if microbrews are your thing.