i have a hard time packing light. i know with alaska, it's tough because you might need layers and you might not. but i wore jeans and leggings underneath for outings. i could have done with like 2 pairs of jeans period for my entire pants wardrobe. i wore long sleeved t shirts and had layers of tank tops, short sleeved shirts and pull over sweatshirts. and a jacket. and i just did the shell type jacket to add waterproofness. honestly that i only wore once, although that's not something you could choose not to bring. i brought tennis shoes and uggs and hiking boots. i did not need the thinking/waterproof boots. i suppose you could depending on your excursion choices.
basically, because of the time change and the hours of daylight, i found it incredibly easy to do laundry this trip (usually neve do laundry - or you could pay for the laundry service). i washed all the things i brought twice, so i could have just brought one pair of pjs, fewer t shirts, no pants other than jeans (and one dressy outfit", one pair of sweats, fewer socks etc. my husband and DS didn't pack terrifically less than i did, but they had no interest in me doing laundry for them, whereas i enjoy laundered things immensely!
we were on last years 9 day trip, with 2 days before and after. i could never be a cube person! but, again, it was easy to do laundry and i so i did! and didn't miss anything or wait because i usually did it at like 530 in the morning! also, i typically bring a pair of older sneaks (and the uggs too on this trip) that i specifically plan to leave behind so that lessens my return luggage a little bit!
wrapping my mind around packing was the hardest thing for me!
ETA - i enjoy a persimmons scarf and they were handy. so i would be sure to have a good ski cap/hat and a decent pair of gloves. we too were super cold on tracy arm day (but so fun!) and i mostly liked the layers with the hat and gloves.