How about decorating your condo while he isn't there and having a cake and a pinata for him.
If there are two adults there on your trip, have one of the adults take him out for an hour while the other adult decorates the place and spend the day in the park.
When you come home, surprise him with the decorated condo and enjoy the cake along with the pinata.
You could collect little trinkets from the Disney parks to put into the pinata and even Disney Dollars.