Hi Bill. I've been to Bermuda several times... it is a beautiful place, and easy to get around by local transportation and ship excursions.
As this is your first time to Bermuda, I do recommend the Bermuda Island tour. If this is the same tour I took -- 5 hours -- it is fabulous and really gives you the lay of the land. You see a lot of the islands and get off at several points of interest. I believe I waited until my third visit to do this, and still enjoyed it.
Getting to Horseshoe Beach from King's Wharf is easy by public bus. I believe it's the #7 that goes to the South Shore beaches. Let the driver know where you want to get off the bus. It's then a walk down a steep hill to the beach. Last time I was there (summer 2006), a van would bring you to the top for a couple of US$ per person if you didn't want to walk.
I haven't done the segway or glass-bottomed boat tours, so I'll leave it to someone knowledgeable about these to comment.