I read this book ages ago. The details are fuzzy.
14 year old Jamie, aka Punkzilla, is AWOL from military school and on the road heading for his dying big brother. Told through a series of letters to his brother and other members of his family, the book shows Punkzilla's journey on the road, as well as his inner journey away from being a screw-up.
As is common in Rapp's other books (33 Snowfish), the subject matter and the language are raw and edgy. Punkzilla's trip is not an easy happy one--it is disturbing and gritty and nothing that a 14 year old should ever go through. The end of the book is not a nice sitcom ending, but it is somewhat hopeful that Jamie might actually have found a place he can belong.
I would definitely recommend it for older teen readers and not the younger tweens.