gun? lol
i'd go with bigger tires.. you don't need the snorkle.
extra fluids, tools, fuses, bulbs, tire pump, jack... clothing you can layer for the cold. pan for gold panning.. batteries and charger, camera, i agree on FRS... learn about the weather and watch the skies. camping gear. you should basically be self sufficient. alcan has traffic on it but if you go off somewhere then who knows if you'll ever see another human.
also learn how to build a fire as 99% of peeps have no idea how to do it and when needed it's the best thing ever. i would say it is the number 1 thing to know in the wilderness.
map and compass and learn how to use them. yeah you can have your GPS too but map is irreplaceable. learn how to use the unit also.. remember that you will need batteries for this pup too.
plan, organize and check everything 2x.
have a blast and we better see a bunch of pictures when/if you come back.