On Nantucket Island, explore the tightly knit, cobbled streets where hundreds of grand homes were built by ships' captains in the 1700s. Then visit the Whaling Museum for an upclose look at a sperm whale's entire skeleton. When in port at Edgartown on Martha's Vineyard, sign on for a tour of the Cape Poge Wildlife Refuge on nearby Chappaquiddick Island. You'll bounce along the sand, seated on benches in a flatbed truck, learning about the ecology and history of the island along the way. And finally, there's serene little Cuttyhunk, the scene of the tour's farewell New England lobster boil, held in the waterfront backyard of a local island family. Save room for "lobster tracks" ice cream (red-candy-coated caramel in fudge-brownie swirl) at the marina before shuttling back to the Arabella, anchored offshore. End the night beneath a cozy blanket, star-gazing on deck.