For kids, don't rule out the train!
I first went on the train in 1972. The last time was in 2001. And I'm going again next year.
It was the most magical memory of my childhood. Some of the trestles are high and exciting. The tunnels are exciting. And it's fun looking off for wildlife! It's a narrow train with old fashioned motions.
They have a few excursions now that are for more active people. You can take the train and go on a hike, or kayak across a lake.
The rest of Skagway is a bust. Silliness about the goldrush, and not all that accurate either.
I also found an excursion that takes you to Haines, and cruises you around a wildlife preserve nearby. That's a new excursion where you are likely to see moose. You won't have opportunity elsewhere, because moose haven't made it across the mountains to the rest of Southeast. I think I'm doing that one next year too. It's hard to find excursions for active people. Even the 4 wheel drive excursions are boring. (been there, done that in Ketchikan)