We took fleece jackets and that was fine. In Sitka we were a little cold, probably dressing in layers is the best bet. We did not have any rain. It was cool (60's or 50's), but not really cold.
Our first 24 hours we had high seas and everyone was a bit sea sick, some more than others. After that no problem. Sunday we got on the boat.
Next day was Glacier Bay, you don't get off the boat, I recommend going to the bow of the boat for best views.
On the boat, I paid for a massage, and also to use the jacuzzi hot tub that you have to pay extra for. If I was doing it again I would skip those expenses. We did use the hot tubs that are free and they are just as good.
You have to pay for sodas, if you get a drink card for sodas you can get $50 of sodas for $25. We bought laniards to carry around the room key like a necklace, you might want to bring some along if you have them.
The piano bar is good, the magician/comedian is really good, the entertainment is pretty good overall. For photos, you can get all your photos for $400 including negatives, or buy them by the sheet. We bought just a few by the sheet, but someone told me that they planned to buy all their pictures so they got as many taken as they could - there are 5 stations set up for photos on the last formal night, and they had pics taken at all the stations. There are many opportunites to get photos, and the formal posed ones are really well done, so it might be worth it to have that strategy.
WiFi is very expensive, 75 cents per minute, or 55 if you buy 90 minutes. Way too expensive.
We were also on 5th deck mid-ship with a balcony, it was nice. The rooms are adequate, the beds were comfortable. The service is very good. Overall we had a great time.