How does Fox end up in this world? Or are the characters from it coming into hers? It's possible that you haven't played up this concept enough, if ways to make it obvious aren't coming to mind. It sounds like a really good idea, though.

I'd say have Fox be the one who does the exposition. Have her be struck by the resemblance to X stereotypical character, or of a character from such-and-such book that she read. She does own a bookstore, after all. Make these characters as Troperrific as possible, so that interacting with them is a veritable Cliche Storm! (Links contain some offensive language and things.) And they have different trappings and things, but she starts to realize she can predict their behavior just by thinking what so-and-so would do in this situation.

Each time she meets a new person on this adventure of hers, she starts trying to determine which character archetype he or she is. By the time someone actually explains it to her, it's less of a surprise and more of a confirmation.

Bonus plot twist: Fox herself is the embodiment of a character archetype, but doesn't realize it (and won't until someone tells her).