There's not too much flat riding in Vermont... For our first tour we tried out Trek Travel on a weekend tour of the Stowe area, so we could drive there. Some of the people on the trip were from the midwest (triathletes) and were challenged by the climbs. I would vote for Maine. Coastal areas are busy in the summer, it could be rainy and cool, too, but there's plenty to do, besides ride. I love mid-coast Maine (Camden and Rockport)