Whenever it rains it is typically cold. On a remote wilderness trip, Alaska's sometimes-unfavorable weather can introduce the hazards of hypothermia. Alaska's guides swear by heavily rubberized canvas overalls and hooded jackets designed for commercial fisherman that are tough and won't tear out. Tough, long cut and oversized, waterproof raingear is what you want. They are a bit cumbersome to walk around in, hard to pack, and can be hot on a warm summer day, nevertheless, in wet, cold conditions they are optimal.
Wet suits are less desirable, except in the fiercest of white water canyons.
Wearing a wetsuit for the duration of an entire trip will be uncomfortable, especially putting it on wet on an already chilly morning.