M.C.
I went to Alaska when I was 16 with my parents on a summer vacation. But we drove. Here are the things I remember from the cities you mentioned...
Juneau - Mendenhall Glacier. It's HUGE, and you can get right up to it. I think there are trucks/buses that go out on the glacier, but you can also just stand back and look. As for restaurants, we went to the Fiddlehead Restaurant there. It was so good we bought a cookbook, and still use it 16 years later.
Skagway - I think this is where the old train ride is. Beautiful scenic views that I still remember.
We didn't make it down to Ketchikan and I'm not sure where Icy Strait Point is. Hope this helps some.