I normally don't do tours, but the Conch Tour Train sounds cool.
Recommended meals:
• Breakfast at Blue Heaven on Thomas Street
• Dinner at Mangia Mangia Pasta Cafe on Southard Street
Must See:
• Ernest Hemingway Home and Museum on Whitehead Street
• Dry Tortugas National Park
• Mel Fisher Maritime Museum
From 1996, a Key West FAQ.
From 2015, 36 Hours in Key West .