We had no planned excursions here. As soon as you get off the ship & on the dock there are multiple companies offering shuttles & excursions.
Mendenhall Glacier - We paid $16 roundtrip, on the dock. This was one of the better tour guides we had, very informative, I thought he lived there but it was just a summer job for him. The shuttle really drops you at the corner of the welcome center culdy sack parking area, very near the bear viewing area, we saw no bears but others did, we did see spawning fish, ducks, & 2 baby porcupines. My mother went directly to the welcome center note, they do have a elevator up to the welcome center, she didn't know that & ended up walking up the ramp. Rest of the group walked around the lake area, saw icebergs & was able to pick a few little pieces up out of the water! We did the hike to the waterfall, I'm not in great shape & was able to do it (slowly), started raining a bit the umbrella came in handy again. Rest of the time we walked around Juneau shopping, there is more to do in town but after the hike I was fine with just shopping.
Tram We dropped into this as we walked back to the boat, late in the day. I thought it was expensive. If I was going to hike around & use the trials, I might not have a issue on the price. It was rainy, but the views were still nice, it was also nice to see the bald eagle they have.
Whale Watching - Since we're from Southern California I didn't even look into Whale watching, but some people on the ship did go & saw a TON of whales, I do wish we'd done it.