Help: 44 Mag or 454 Handgun and Recommended Ammo for Extended Stay in Alaska
I'll comment on the X frame S&W (460 & 500). Yup, they are the most powerful of the commonly available handguns but I sold my 500 after only a few months (not sure exactly how long... Less than a year for sure) of ownership. Would I complain about the hurkiness if I ever had to face a mean critter? No, I wouldn't. But it really was awful to carry, may as well been hauling a rifle. In the end I decided to sell it and go with a Ruger Alaskan in 454. I always had that with me unless I was packing a rifle, and even then I still had it with me sometimes (like when calling for predators only armed with a .243 or .223).
Keep in mind, your defensive gun is only worth having if it isn't a burden to pack.
Also, an earlier poster said that your odds of being charged by a brown bear are slim. He is absolutely correct. I lived, fished, hunted the Kenai Peninsula for ten years and only saw 3 brown bears and was never charged. I did see gobs of black bears, especially while in the high country. If you are going to the Mat-Su valley your experience should be similar, still. Be prepared.
Other parts of AK you will see lots more brownies, Kodiak, AK peninsula, ABC islands etc.