Anderson writes beautifully, particularly the descriptions of the natural world. She also is honest about her experiences and how they changed her. 
While I think the subtitle is accurate, I don't think that theme was adequately explored throughout the book, leading to a rush at the end of the book to show her transformation, as well as purple prose that undercuts that defining moment. Yes, I think she had that defining moment on the trail, more reflection from the author throughout the book would have improved the book overall and made the ending more genuine.