I hear Holland America is one of the best lines to pick for Alaska because they have preferred docking locations and routes.
One tip, make sure the times you will be in port. Alaska can be strange as far as port times, I wouldn’t want early morning dock, leave early afternoon times myself. Especially if you’d like to go on shore to shop or eat.
I’m not familiar with HA, is there an option to upgrade? I personally would pick the room and not have a guarantee room as I’m a control freak person. A forward cabin doesn’t sound ideal with motion sickness though. Not sure if the guarantee room was cheaper?
Sounds like a great trip. If you like YouTube videos, I find that they are very informative. Lots of options with cruising.