I paste a link to a google map of my 37 mile looping ride from Sherborn to Claybrook, Strawberry Hill to Pine Street and back. The roads are classic cruising roads of smooth pavement, low traffic and swooping turns. Moderate hills, lots of shade and did I mention smooth pavement?
The Prouty is the PMC of NH benefiting Norris Cotton Cancer treatment, a great cause. There are various distances of walks and rides. The figure 8 course loops back and forth across the Conneticut River into Vermont and back to the NH side there are flats and significant hills.
Generally low car traffic, well marked and very friendly. About 5000 riders but no crowds because Prouty uses a "riders choice" start rather than the enmass crowd. We've camped the night before and this time, got up at 4:30AM and drove up in the morning.
We finished the 50 just after noon. We opted out of the 100 mile ride in concern for getting caught in thunderstorms and big hills on what would have been daughter's first century. Daughter and weather were fine, Father too cautious. We'll do the TriStates Century in September.