Client was open to other design concepts, but here is a concept he is thinking about right now:

The body of a young (18-year old) cowboy is floating, lifeless, in a river. The hero of the book (the "accidental sheriff" from the first book in series) is trying to save him / get to his body. Perhaps the hero could be wading in the river to retrieve the young cowboy, or perhaps he could be on land, moving towards him upriver. Also, the hero has a pet dog -- a huge, wolfish-looking dog with thick gray hair -- that find the young cowboy. Maybe the dog could be part of the scene, too --- either in the river or on land.