3 day tour starting near Keene, New Hampshire

I am planning 3-day loop, starting near Keene, NH (actually, East
Alstead/Lake Warren), about 50-60 miles per day with stops at inns or
B&B's. My first idea is to go up the Connecticut to Hanover, then to
Bristol via Plymouth, and then return. I don't really know the roads,
so suggestions about this or alternative routes (maybe into Vermont?)
would be very welcome.

Thanks,
Tom