I think that as long as you stay off Route 7 between Pittsfield and Stockbridge it's pretty much all good. Route 7 south of Stockbridge, going toward Great Barrington and Egremont, has some of that Berkshire quaintness but is less congested. That would also allow you to head back toward Canaan on Rtes 23 and 22 through Hillsdale and Austerlitz in NY, not as cute as Lenox and Stockbridge but pretty country.
Or you could head east from Lee and get on Route 8 and head either north or south; there may not be much of a shoulder but you should have the road to yourself most of the time.