Status Updates From The River (Hatchet, #2)

In pages 23-40, Brian returns to the wild, makes a plan to survive, and gets rained on enough to look like a drowned rat

Brian Robeson, famous for surviving the wilderness, is visited at home by three men in suits from a government survival school who ask him to "do it again," with a man named Derek Holtzer, on a wilderness training expedition to teach survival skills, much to Brian's initial reluctance but eventual agreement, leading to their setup in the woods where they abandon most supplies for authenticity.