RE: What do you wear on your head?
I wear a lightweight full head cover with a ballcap on top of that. Then I put a camo mesh face mask/neck gaiter on to cover my face and neck. It's the only way to keep those monster skeeters off in warm weather.
In the cold I wear two camo fleece neck gaiters. One on my neck and face, and the the other upside down on my head like a watch cap. That way if my head starts to get too warm, I just adjust the size of the hole in the top.