I get seasick easily so I always choose a cabin mid-ship at the bottom. This is the most stable area of the ship. We book an inside cabin as we don't spend much time in the room and prefer to spend more money on other things. Last cruise we booked an inside guaranty were upgraded to an Oceanview which was a very nice surprise.
Other costs would be tips (most lines suggest $10/pp per day to be divided among your waitstaff and room steward), any alchohol, pictures, on board purchases, sodas or soda cards, shore excursions, spa services, casino, or eating in a specialty restaurant (not sure if there is one on the ship you plan to travel on).
I haven't cruised on Norwegian yet, but have friends that have several times and have had no complaints. I have been to Bermuda several times on land vacations. Its a beautiful island with friendly people. I would recommend eating all your meals on board, however, as (1) you've already paid for them and (2) I found meals in Bermuda, especially dinner, to be expensive.
Have a great time and if you have any questions feel free to email me.