Where in Alaska are you going? People like to talk about Alaska like no matter where you go, it's all the same. Problem is, Alaska is huge. It's area is equal to 1/3 of the United States. Southeast Alaska is way different than South Central Alaska, which is way different than the Interior, which is way different than say, Denali National Park. I live in Sitka, which is in Southeast Alaska, about 100 miles, as the crow flies, SE of Juneau. Although I can't give you any specific settings or whatever, here are some tips:
-Make sure you have a sturdy tripod. If you don't know why, let me just say that 90% of when I shoot, I'm on a tripod, regardless of light. Low ISO, stopped down with CPL means you probably need a tripod. Just because there's between 16 and 24 hours of light (depending where you are) in Alaska, doesn't mean you don't need one.
-A CPL is basically a requirement, especially if you're lucky enough to visit during clear days and/or you're anywhere near the water.
-If you can, make sure you can cover a wide range of focal lengths. If you can cover between 24-300 (35mm equivalent), you should be doing great. If you can cover more, than that's even better. Alaska is one of the few places where one second you're preparing to take a beautiful landscape, and the next second you need to be able to shoot an eagle catching a fish. Rent lenses if you have to. In addition, try to bring at least one fast lens (50mm f/1.8 would work perfect). If you plan on seeing any shows (native dance, etc) flashes usually aren't allowed.
-Prepare to get wet. It rains, a lot here. Especially in Southeast Alaska. Although we don't get a lot of the rain shower type rain most places are used to, we get the mist that's more like a thick fog. If you're going to be shooting for more than 15-30 minutes, find a way to protect your camera (if it's not weather sealed)
-Golden hour in Alaska is very early in the morning, and very late at night. In Sitka, where I live, which is fairly far South (relatively), sunrise was at 4:18 this morning and sunset is at 9:56 tonight. Prepare to get up early and stay up late. A nap in the middle of the day might be helpful.
-Protect yourself! Bug spray, bear spray (big can of pepper spray), rain coat, sunscreen (yes, sunscreen, especially if you're on a boat on a sunny day).
-Chances are it's going to be cloudy most, if not all the time you're here. If you have a macro lens, don't forget to look down. We have some absolutely beautiful flora here. Take advantage of the huge softbox in the sky.
If I can think of some other things, I'll let you know, but this should give you a start. If you have any specific questions, let me know, and I'll try to answer them.