This is just my personal opinion, Bermuda is THE one destination you can go on a cruise ship and do it all on your own. Invest $ 15 in a Fodors or Frommers guide book
and then do it all on your own. In St. Georg you can walk the town and most of the attracctions . A mini bus can be taken to Tobacco Bay, St Catherines beach , Achilles Bayand Fort St. Catherines for just a few dollars. In Hamilton you can walk to all the shopping and many points of interest. Take public buses to Crystal Cave, Perfumary,
Botanical Gardens and Glass works. Take public ferry into Hamilton (take the local) and you will see everything you might see on a harbor tour. The glass bottom boat ride is good in St. George. Take a carraige ride in the evening (after the crowds are gone) in Hamilton. Best snorkel tour (3 great stops and a harbor tour on the way in and out) is
run by Jessie James Tours out of Hamilton.Might be the best tour I've ever booked.
Take a bus or cab to Horseshoe Bay. Keep walking on the beach to get away from any crowd. Walking amoung the rocks is a must. Eat on the ship and drink local beer, ale or a Dark and Stormy (rum with ginger beer), in the pubs before and after dinner. Dinner ashore is quite expensive .
Enjoy your cruise.
If you're like me & aren't too courageous about going out on your own (as PapaBill suggests) then excursions are a good idea (even though they are a bit expensive). We took the Attractions Bus and the Glass Bottom Boat ride when we were in Bermuda last year. Our bus driver gave us a good overview and the ride includes a stop at the Crystal Caverns (a must see!). The glass bottom boat was okay but a couple of quick passing storms hit us while we were on the boat which made the waters muddy so it was difficult to see at times. We did manage to adventure out on our own by taking a cab to Horseshoe Bay. The waters are soooo blue & warm! Suggestion: bring a bottle with you so you can bring back some beautiful fine pink sand as a souvenir. Make sure you leave enough time to get back to the ship because there's no "taxi stand" -- you just have to wait in the parking lot until a cab comes along that's dropping someone off at the beach. Have a great time!