I hope you don't mind if I jump in, janfred. The Bermuda transportation system offers several types of passes for travel on the bus and/or ferry. The last couple of times we were there, we purchased the 3-day passes and they were very well worth it. Ours covered the ferry, as well, which was the easiest and quickest way to get from St. George (where we were docked) to King's Wharf. The ferry terminal will be very close to your ship, and you can purchase the passes there.
I haven't been to Somerset beach, sorry.