J. A. Darke 
Bigfoot Island [PDF ebook] 

Pine Island is a remote getaway for campers and hikers. So when Darius and the rest of the Wilderness Warriors show up for a late summer trip, the area is practically empty. The group sets off into the woods, but they soon experience eerie sounds and strange sightings, as if they’re being tracked by something that is not quite animal, but not quite human. When they wake one morning to find their guide’s tent empty, the Wilderness Warriors discover that their terrifying journey is only just beginning.