Definitely a 12 gauge. Don't know how you could do without the 4x4 of guns... so many ducks, other birds, for bear protection, and for "jellyfish trap."
Don't know if any of you other costal guys have done this... but you take some rubber tubing and duck tape with you... make your self a big sling shot, and do yourself some trap shooting with those thousands of moon jellies that wash up on the beach. -You can just throw them, moons don't sting like lions do. Or maybe that is just in seward that we do that.
Hell, I already live in Alaska, and I would still like to start "accumulating" more guns as you say.
I think a mid level like an -06 or a 7mag is indespensible, as well as a .22. If you are interested in larger game like ox or brownies... just do what I did, let the guys at the shop talk you out of the .375 and into the .458. That whole "Alaskan ammo availability" complex that everybody else seems to have... just isn't true. We do have sportsmans warehouse. We do have mail service. It's a supply and demand thing - there are A LOT of shooters in Alaska, so there is a lot of ammo supply.
One things... which some people don't agree with... but I do agree with... myself, haha, get rubber raingear. A full set. Hell, get two. After two or three days of walking through soaking wet brush with a full downpour.... the whole time... even the expensive gore-tex will let through some amount, and retain some amount of moisture over time. Just bring an extra pair of long johns to wear underneath - the rubber will never retain water. That is only in certain cases of course. Well for me it should have been most cases... but that is what happens in a rain forest. Even the super expensive gore-tex super lined coated with some space age crap expensive stuff, will not breath enough to get rid of all your sweat if you are working hard. I've tried a lot of it. It's good for being lightweight, that is about it. - If you are not into mountaineering, you probably don't need it. Finding a silent rainshell for hunting, that is a different story all together.
As for clothing, I like bringing more of lighterweight clothes than less of thicker. And not always as a layer. Just keeping an extra set or two of lightweight long johns seperate can be a god send. Light weight long johns -dry- under good raingear can keep you pretty warm as compared to the moist mid or heavy-weights you have been wearing for three days straight. One other thing along those lines, is make sure you have enough underclothing to keep you warm. When it is not precipitating, I don't like to wear a shell. That cool wind you feel without your shell is cool because it is carrying away moisture. Better to wear a little thicker shirt, or two thing shirts than a light shirt under a coat when you are not worried about rain and are worried about sweat. That is why I don't like coats. I only own one thick coat, and it is for around town or around my property. When I am out in the woods, I have a few unlined shells for different purposes (rubber, goretex, something that rei made 15 years ago that sucks for rain but is good for snow... etc. - because like I said before, I like smaller layers. Coats are big, hold moisture well, and don't breath. -So those big puffy coats you see... for extreme cold weather only. Or rap music videos for some reason, must be cold on those sets.
Lastly... one of those most important things you can have up here are gators. Not the big green things with sharp teeth to protect you from bears, but good, durable, waterproof, gators. All that water, snow, brush that your expensive clothes and boots supposidely protect you from mean nothing if you leave a giant hole under your pantleg. The ones I have now... goretex gators from cabelas. I hate them. they are quiet, they are light, they fit snugly, they block stuff out well... but they retain water like nobody's business. I need helly hanson to make some stretchable rubber ones... One thing i always have with me is a roll of double sided velcro, so if I need a pair of impromptu gators for mypant legs or wrists I have them right there. Light, reusable, handy, why doesn't everybody carry double sided velcro?
I guess for gear, my number one recommendation, and in agreeance with sourdoughs comment about different environments, is to plan your gear for you trip. There is too much environemental difference to have one set of gear. It's kind of like the "all around Alaska gun" disscussion going on right now... Nothing will work in all situations.
Oh yeah, and don't forget to keep your toilet paper in a ziplock bag.