Please tell us a bit about yourself. Ages? Children? Likes/dislikes? Disney fanatics?
Cruises (in general) are wonderful and Disney cruises in particular are really nice. First, resign yourself to the fact that you won't see/do everything there is to do. In fact, some folks prefer to do nothing at all but just enjoy the ship.
Dining in the MDR will be fun. There are also two adult-only dining venues that you might want to consider, Palo & Remy. Take a look at the reviews in my Sig below.