Ahoy, Elise!
One of the most difficult parts of booking a Disney Cruise Line vacation is choosing a stateroom. I usually try to find a stateroom that is "sandwiched" between other staterooms, meaning there are cabins both above and below the selected room. I also try for a room that is midship, so that many of the main dining rooms and the pool decks are all about the same distance walking. My favorite location on the Disney Fantasy is deck 8, midship.
When you are docked in a port, often you do not have a good view, as there are cruise ships docked next to you. But, when the Fantasy docks at
Castaway Cay, you will want to be in a starboard (right) stateroom, so that you will have an ideal view of Disney's Private Island Paradise. From the ship, you will be able to see much of the Castaway Family Beach.
I hope this helps with your cruise planning, Elise! The Eastern Caribbean itinerary is wonderful. Please come back to visit us here at the Disney Parks Moms Panel with any questions that arise as you get further into the planning process.
Happy Cruising, Tracy V.