RE: Keeping your feet warm.
Sometimes your feet get colder than other times, depends on how much they perspire. I rub my feet with Secret Unscented after I shower at camp. It keeps your feet from perspiring as much and serves as a Scent blocker from your feet.
I never use Cotton socks, cause they make your feet perspire. I always use Wool socks and change them every day.
Also remember, in a sitting position with your legs bent at the knee for long periods of time,slows circulation to your feet. Try to stretch your legs from time to time.