Thanks for even more suggestions! I hadn't heard of THE EDGE OF EVERYTHING and that especially sounds like something my students would like. I ended up buying GREAT FALLS by Steve Watkins, ICE DOGS by Terri Lynn Johnson, and ORLEANS by Sherri Smith, which also don't quite fit the bill, but they're good reads that kids have enjoyed! I have found it interesting that there really are so few modern adventure / survival books, when those types of stories are so appealing.