I know others have mentioned it, but I can't help but suggest Gary Paulsen. Hatchet was one of my favorites as a kid. Now I am a 6th grade teacher; once I started teaching a reading class, Gary Paulsen's Hatchet was the one book I knew I had to use. I have found a lot of boys who never want to read, love his books. I think most of his books are about the 5th grade level, but are pretty simple stories to follow. There is the Brian series (Hatchet, The River, Brian's Return, Brian's Winter, Brian's Hunt) that are about the wilderness and survival. One that I read this year and really enjoyed was Woodsrunner, about a teenage boy during the Revolutionary War whose parents were captured so he tries to track them down and rescue them.