Ever boarded a cruise only to realize that some of the activities you were most excited about were already booked? We have, and we want to spare you the same experience. This is especially possible on Disney Cruise Line, but for a good reason: No other line has quite the depth and breadth of activities available on every sailing. There’s a lot to choose from, and most of it you can select once you board. Read on for those exceptions you really need to address in advance, or risk missing out on.