Buy a 3-day pass, I think it's about $28 pp and you can use the busses and ferries on an unlimited basis. This is is the best way to get around.
We took the bus to Horseshoe beach (beautiful beach) then down to the Dockyard and took the ferry back to Hamilton.
We got up one morning and took the ferry from Hamilton to the Dockyard, then caught the another ferry to St. Georges then took the bus back to Hamilton. The bus goes to the Aquarium as well. You can get on and off.
Seeing Bermuda from was the water is wonderful. You also get a chance to meet the locals going to work.
I went to Bermuda last May and the weather was wonderful. Hope you have the same.
Bermuda is a wonderful port. Have fun.