Re: 10 days south of Cuttyhunk
Mystic if you have kids and stay in the seaport
Not a huge fan of Greenport but it has been a long time
Shelter Island was very pretty and very quiet but also boring and too quiet.
Fishers Island is OK but you feel like your not supposed to step ashore
Stonington would be on top list except that is is right between Mystic and Watch Hill. If you need a good marina with a restaurant, laundry, etc. Dodson's is hard to beat.
I have never been in 3-mile Harbor nor Montauk...need to check them out.