I dont think that there are any ? or if so very few from the West Coast----thinking Seattle that that are that short ? under 7 days that is--and go to Alaska.
Ive done one from San Francisco up to Vancouver and then another one from Seattle that was only 4 days but didnt go to Alaska---just to ports in Canada-----Victoria and Naniamo-----
Alaska is great-----and calm waters------I've done the roundtrip from SF and back several times and it does get choppy going around the bend--lol--
Enjoy whatever they choose