We had an Oceanview Stateroom on the Wonder last May, and spent most of the day up on deck. I found myself moving about a bit from Deck 4 to Deck 10,forward to aft, port to starboard, etc. And part of the time indoors. As said before, Tracy Arm day is about a LOT more than just the glacier, and many people saw bears at one point. (Dang! Missed them!)
Our cruise was the first of the season, and there was still a lot of ice along with seals & their pups, so we were not able to get really close to the glacier anyway, but the scenery is spectacular all day! Waterfalls, and someone spotted mountain goats up REALLY high on one of the mountains we were passing. It took me quite a while to spot them between looking through binoculars and trying to eyeball where they were. It looked to be a big family of them, and they were teeny little white specks way up there, but very cool to see with binoculars! Do NOT forget your binoculars and camera!
If you stake out a spot early in either the Outlook Cafe (adults only), or a deck chair early, you would still be able to catch much of the scenery passing by, though you would not be able to look down and spot any wildlife most likely from that vantage point.