Your toes and hands will have the most difficult time keeping warm ecspecially when you stop moving. Instead of building a tolerance to the cold, over the years as your hands get exposed to more and more cold, your hands will get colder easier and faster as the years go on. I always have a pair of wool fingerless gloves, wool glove liners, and my lamilite mittens. I've tried the beefiest gloves I could get my hands on but they never work, mittens are needed for the real cold.
Best way to really learn is to get out in it. It takes years to really know what your doing year round in the bush.