Stuck right between SF and the East Bay, Treasure Island isn’t a destination most tourists (or even locals!) visit. But it hosts great art festival monthly, and music festivals annually. There’s also a lot of room to bike and a few wineries that are worth a visit. Visit before all the spooky former government buildings are knocked down to make room for commercial development. Take a bus over from the Embarcadero or drive. There’s no ferry, yet.