Alaska is a beautiful, must see destination. Seeing it from a cruise ship is not the most ideal, but it is convenient and fun. The first day and a half is spent at sea with nothing to really see. Ketchikan is not the best port and we could have easily skipped it. Juneau was fun with a lot of excursions to choose from. We ended up taking the bus out to the Mendenhall Glacier and spent a few hours there; hiking out to the falls and back and then around the visitor's center; we also spent some time in the center and watched a short movie there. It was well worth going. The bus was about $35 per person round trip. Be careful, a lot of people try to sell you the bus tickets and not all of them are directly connected to the bus company. We then went on an excursion to one of the Alaskan huskey dog training places. It was fun and informative.
Next stop was Skagway. We really enjoyed the town and loved the excursion out to the Davidson glacier. The guides were great (both on the boat from Skagway and on the little trip to the glacier). Highly recommend this excursion. The next day is spent on the ship but you go into Glacier Bay and that is, in my opinion, the best part of the trip. My only issue is that, being on a large cruise ship, you don't see any of the humpback's up close; however, we saw a fair number of them and even caught one breaching. We also saw a lot of sea otters, seals, sea lions, eagles etc. And, of course, many glaciers. The next day is also on the ship and you go to see the College Fjords. This is also very beautiful and worthwhile, but I enjoyed Glacier Bay more simply due to the diverse wildlife we were also able to see.
The on-board naturalist was great. She mingled a lot with the passengers (in addition to the formal lectures she gave in the theater, which were also good, and the time she spent at her table set up outside the theater). It was great spending time with her out on the bow of the ship because she helped spot wildlife and even had extra binoculars for people to borrow for short periods. She was great at telling you the best times to be out there looking for wildlife.
we like Vancouver a lot; we stayed there for 3 nights prior to the cruise.