I'm not sure I have a lot of insight about the longhairs, but I'd tend to rule out them being miners. I think that would put a lot of dirt on the cap (especially coal mining), but I think most miners would be wearing hard hats, so it's unlikely he would wear the cap too or that it would have that dirt pattern. Oil workers, maybe? Though I think the hat would be dirtier and probably unwashable.
The Carhartt jeans would suggest some kind of outdoor blue collar work like construction, logging, farming/ranching or hunting. It probably doesn't go along with rockers or metalheads. Someone mentioned sawmill workers and that's possible, but having long hair around powerful and rapidly spinning machines sounds like a bad mix.