Some of the suggestions will depend on your family: are they the type that wants to learn history, see wildlife, do something active, etc.?That might tell you whether you'd get more out of something like a zipline, kayaking, a fishing trip, boat sightseeing, plane/helicopter rides, hiking to see glaciers, historical tours, Native American history, shopping, etc. For our family, it's kind of a challenge as our older daughter is much more into seeing new things and learning new things, and the younger one almost doesn't care about any of that, as long as she can be active.
Regardless, though, I'd recommend looking at making your own arrangements (rather than the Disney excursions): much cheaper, and I felt we got much better and more personalized experiences, and better use of our time. Obviously, if the Disney excursion is the only way to do something, you're stuck, but otherwise look at the places that offer port excursions.
In Skagway, for our family (and really just about anyone) I would highly recommend the Chilkoot Charters Rail/Bus tour. It was awesome, and in our case ended up being tailored more to what our family wanted to do (it's not a very "active" excursion, but it was varied and unique enough that my younger daughter still liked it). In Juneau, we did both whale watching (morning) and the Mendenhall Glacier (afternoon), and these were both things we enjoyed. Our planned excursion (float plane) in Ketchikan was rained out (so...much...rain... - it was the rainiest day of the summer in what is the rainiest town in the US!), and the tour we ended up finding at the visitor center on was pretty underwhelming (though the massive drenching we received most of the day was probably a factor, as well). Others on our cruise seemed to like the lumberjack show there, but we had just seen one in Vancouver (Grouse Mountain), so we skipped it.
Here's my longer review, from our trip a few years ago. It's on a thread where lots of people discussed excursions, so you might get other ideas there, or in trip reports:
https://www.disboards.com/threads/a...ur-reviews-here.2723087/page-69#post-52093898