Where's the Next Shelter? just came out last month and is getting rave reviews. It's about as different a book as you can possibly get from Wild though.
The main character isn't trying to overcome a drug problem or sex addiction. He's just a guy who really loves backpacking, hits the AT and immediately finds himself in over his head. He meets some of the most interesting and hilarious people on the trail and really brings them to life through realistic dialog and vivid descriptions, not only of the people but the remarkable beauty that the trail offers.
Without spoiling anything, the author faces difficult physical and mental challenges that end up providing answers to questions about life he never even thought to ask. This serious fare is balanced with a sprinkling of humor, beautiful descriptions of the scenery and just enough factual information to be of some use as a planning guide.
I should probably also mention that Where's the Next Shelter? was written by me.
Thank you for looking!