I really liked this story! It has a lot of heart and humor (a great example of both in my opinion is Sally playing with sock puppets to keep herself sane while she's sailing alone). Giving the rock creatures personalities was also quite charming.
Even though the story is relatively short and simple, it still managed to surprise me a few times. When the Purple Crane is revealed to almost like, take control of, anyone who has it, and also learning about Sally's true motivations. These made for good reveals that I think really elevated the plot.
Good characters, good plot, good book!