One more thing to ponder. Gothel tells Hook that she can only leave if she leaves some one from her bloodline. She also says that Rapunzel managed to trap her in the castle. So either Rapunzel and Gothel are related in some way, or Rapunzel managed to make a curse that added this little bit to ensure she was trapped forever (not thinking that anyone would come to Gothel’s rescue).
Also, on second watch I did hear that Evil Queen did tell Wish Hook the tower was in a ‘distant realm’, so I guess he did travel to it somehow. It just seems awfully convenient that he happened to be there again.