KEEPING BOOT INSULATION DRY: 1st you must have Gore-Tex boots. 2nd wear 3 mm thick closed cell neoprene divers' socks over thin polyester liner socks. Change liner socks every night and turn the divers socks inside-out to dry at night inside your sleeping bag so they are warm in the morning.
KEEPING BOOTS WARM AT NIGHT: Cold boots on a bitter cold morning ae not only miserable but increase the danger of frostbitten toes.
SOLUTION: Put boots in a stuff sack and then in your sleeping bag at night. Of course you will need a size Long winter bag. THIS is why it's always better to have boots with removable insulating liners like felt pacs or plastic backcountry ski boots.