This is a delightful series for tweens, young teens and adults. I enjoyed this book too even though the recommended ages are 10 to 15. Since it is Christian fiction, it doesn't contain the kind of material you really don't want to expose your children to. It's amazing what they put in books for this age group.
I did not think it worked well as a stand alone. I would recommend that you read the first book, The Glass Castle, before this one. Since I read the previous book months ago, I was a bit lost when I started reading this. Bits and pieces came back to me as I continued, and I was grateful for that; however, there isn't enough information if you begin with this one.
I appreciate how the authors incorporated prayer and faith into the story. The plot is one I enjoyed; however, the book ended in a mild cliffhanger, and I am looking forward to the next in this series.
I highly recommend this book.