Depends if you plan to eat at the castle I guess. BBB in the castle is located right next door to the restaurant. Plus, if you DD plans to walk around the park all day dressed like a princess, it's nice to be AT the MK. She'll get a lot of attention from the CMs and may get picked as the "Princess" at the Laugh Floor attraction. DD did and she has not forgotten it. She still tells people that the Monsters, Inc characters think she's the "Princess of Massachusetts"