A quieter alternative to Put-in-Bay, Kelleys Island sits 4 miles north of the Marblehead Peninsula and is reachable by ferry from Marblehead (about 40 minutes' drive east of Sandusky). The island is small enough to cover by bike — most visitors rent a golf cart at the ferry dock — and is famous for its Glacial Grooves on the north shore, a state memorial preserving the most dramatic exposure of ice-age glacial scour in the world.
Beaches, a small wine maker, hiking through Kelleys Island State Park, and a relaxed village around the ferry dock. Day-trip from Sandusky or stay overnight at one of the small B&Bs.