Hi, MJ ...
"Cruise Dresser", hmm? Don't give me any ideas ...
And, yes, I have a "cruise closet". It's just not very organized.
My theory on daytime Alaska dressing is two words: Lands' End
2-3 pairs of khaki-type pants, 2-3pairs of shorts, turtlenecks, polos. I wear the polos OVER the turtlenecks under a cardigan sweater. If it gets warm, you can nip into the ladies' and ditch the T-neck. You can use the ship's laundry rather than packing a different outfit for each day.
You don't pack sweatshirts, you buy them. Best place is "SOS" in Skagway. Just walk down the street ("the" is almost the operative word) and it will be on your right.
Along with the sweater, take a hooded anorak, a cheap plastic poncho and an umbrella. You will also want to go to the ski store and buy "glitter gloves" to keep your fingers warm in case it really gets nippy. With them, you can still adjust your binocs, snap the camera, etc.
I'd say forget the gown idea, my Alaska experience is that ladies dress a little more casually. The St. Johns sound fine. Black silk pants are the workhorse of my cruise wardrobe, with different tops appropriate to the destination and season. Pack the pashamina shawl in case it gets chilly.
Since you have been on many cruises, you know that you will see anything and everything. Just try to hit a happy medium and you will be fine.
There are some packing hints on the website for the upcoming Let's Get Lei'd cruise <http://pages.prodigy.net/fourcatcan/leid.htm> just substitute the Alaska clothes for the Hawaii clothes !!!
Your luggage will be more limited by the airline -- if you're flying -- than anything else.
Let us know if we can help more. Now, I'm going to go build that website !!!