Depends where you are going in Alaska. Alaskan Beer Company products (Juneau) can be found all over the state. Their Icy Bay IPA is pretty delicious. In Anchorage, visit the Glacier Brewhouse Restaurant and enjoy their wide variety of craft beers. In the Denali National Park, the 49th State Brewing Company is very solid. And in Fairbanks, just about 15 miles to the north in Fox is the Silver Gulch Brewery.
If all else fails...Jack Daniels, Jim Beam and Jameson.