Like Ram, Clapp's and Meadow islands in Marion. Former Mattapoisett selectman Daniel Mahoney lives on Goodspeed Island, connected to the mainland by an old railroad track that used to haul cars of salt. In Wareham, Onset Island is nearly accessible by a sandbar. But every summer about 50 families use boats to get to their summer homes. And they're more civilized than their Lakeville counterparts.
Onset Island has electricity, phones and running water.
You could talk to Mary Crowley about Wickets Island, also in Onset Harbor. But don't worry too much about being shut out. There are more islands. A man once built a windmill to generate energy for a home he built on Angelica Island off Fairhaven. It's unclear if he still uses the place.