Previewed this book for my 12 year old nephew.

Great humor, puzzles to solve, and a couple of encoded messages, which were always a favorite of mine when I was a kid. Good storyline, and a chance for kids to become curious about US Geography.

Objectionable material? There are times that the children are in real danger of being killed. One of the kids drives the family RV for a couple blocks without a license or training. But really these are handled well, and I have no hesitations handing this to my nephew.

Recommended.