That was nice. It's obvious that the author knows and loves the Camino, and I appreciate the added complication—that neither Maggie nor any of the other teenagers in her travel group is there by choice; the Camino is not so much a dream for them as something they have to grow into. (Programmes like this one exist in real life, by the way, and they're not new—perhaps not common, but still, there's a long history of people being given an option of going to jail or doing the Camino or something like it.)
I'm not entirely sure about the balance of character development here—Maggie gets over her need for expensive highlights and huge amounts of luggage very quickly, and by the end I still had a lot of questions about what was going to happen with the other girls. I'd also be curious to know a bit more about Maggie's life after the Camino; I understand why the book ends where it does, but...there's some truth in saying that the Camino doesn't end when you reach Santiago.
That said: this does as well as or better than just about any Camino book I've read at working in Camino relationships: the people you see every now and then, and might see again tomorrow or in three weeks or never again. It's hard to pull off in books in a way that lets the reader recognise the side characters, and be glad to see them again, but also not feel the need for closure with them, and that works well here.