I agree with Lisa. Buy the bus/ferry pass.
Unless you're into scuba diving or golf.
In that case, you better off getting an excursion.
For first timers, or the first time to a port, I recommend getting the cheapest excursion, the bus tour of the islands on the first day. After you learn your way around the islands, and where you wish to go visit more, use the 3 day bus/ferry pass the second, third, and fourth days you're in Bermuda.
Have a great cruise.