My wife and I went on a cruise that stopped in the Cayman Islands last May. We wanted to do something that was "off the beaten path" and be active, so I found a guy that rents bikes, and we rode around the island. The four people in our party made up the entire group (people aren't lining up to physically exert themselves).
It's the best way. Every time I visit a new place, I check the local bike shops to see if I can get a rental to explore the area.
It does make food taste so much better! Nothing like a few thousand calorie expenditure to do that!
