When you enter the courtyard of the castle, go straight forward into the castle, then straight forward again. Now, to the far left is the Queen's chamber where you'll find the Hockey Mask.
Leave the room and go all the way to the right and down the stairs. Down there, you'll find a chest with 100 cash. This is the Crystal Room where the crystals were stolen from.
Go back up the stairs and exit this area at the exit to the South.
Now go up the stairs to the left or right and enter the Throne Room. The King and Queen are there.
Exit the Throne Room to the right. Head North East and you'll find a chest with a Dirty Sock.
Go straight down out the exit beside the chest. Go up and around the tower heading West to the centre tower.
At the top of this tower you'll find 2 chests.
You can now leave Crystal Castle.