The best way to see the glaciers is on the upper decks. I don't know what other lines do. If you sail with Disney, then they'll be handing out free hot chocolate, mulled wine, and other warm drinks on deck that day. The characters will make appearances in their special Alaska outfits, too. There are some shelters to stand under if it rains.
When we went in 2023, there weren't many people on deck because it was cold and a bit rainy, so there was plenty of space. The ship sailed into the area, turned sideways, waited for a long time, and then sailed back out. So, both sides of the ship had great views. How close you can actually get to the glacier is determined by the weather and how much ice is in the water. Disney offers an excursion in small boats for those who want to get even closer.
We had a balcony room and we enjoyed sitting on the balcony when we had some free time, but we didn't have much free time and so we didn't get to use the balcony often. The Navigator's Verandah rooms are nice. They have a big oval cutout instead of a full view, but they're also protected somewhat from wind and rain.