We did Liarsville in Skagway, which is great for kids, with panning for gold (look in the creek), appearance by Donald Duck, a fun show and good food. Did the scientific whale watching (and other critters) that included a trip to Mendenhall Glacier first then small boat ride to check lobster trap, seals and whales...great for kids and adults in Juneau. Ketchikan we did the duck city and bay tour. Also a good choice for us on a rainy day. Most of the excursions are short enough that you have time to walk the towns. They are right next to the dock, so easy access.
A couple of things to remember:
1. Take a good camera...loads of photo ops from start to finish. 2. We went this past June and it rained off and on a couple of days, so take rain gear. 3. If smoking is a concern, don't get staterooms 8000 back maybe 10 rooms (port side). During our glacier day when it is dead calm, the smoke and ash from the 9th deck smoking area came down on us almost all day...yuck! 4. Our last "at sea" day was sunny and the temps were near 80 on deck by the pools. Bring sunscreen.
We will do this cruise again as it is within driving distance (5 ish hours from Portland, OR). Traffic around Seattle and at border crossing can be issues.