You would need to consider where exactly in Alaska you are looking to backpack. Going to Kodiak? Juneau (panhandle/southeastern)? Fairbanks? Anchorage? Kenai peninsula? Denali?
Also what time of year are you talking about?
Different places, times of year, will dictate what kinds of critters you will cross paths with. If its brown bears, nothing less than a .44mag. If its black bears, a lot of people choose the 10mm.
"Every man alone is sincere; at the entrance of a second person hypocrisy begins." - Ralph Waldo Emerson
"People demand freedom of speech as a compensation for the freedom of thought which they seldom use." - Soren Kierkegaard