Radioactive Evolution by Richard Hummel

Jared Cartwright grew up in a loving, caring community, completely isolated from the horrors of the outside world. When tragedy leaves him alone and untethered, Jared sets out to explore the unknown; a world where twisted, scarred creatures roam an earth ravaged by nuclear war while the rich fled to the skies on floating utopias, escaping destruction and leaving the rest of humanity to die.