The Captain Lindsey House in Rockland, ME is a nice place to stay in that area.
Bed and Breakfast in Coastal Rockland, Maine: The Captain Lindsey House Inn
The Maine Maritime Museum in Bath, ME is worth a stop as well.
Maine Maritime Museum: Welcome
May is early in their season but you may be able to pick up a daysail in Camden or Bar Harbor.
Enjoy your trip.
Regards, John