Thanks again! I think we'll most likely book through the cruise line, since the price difference is $10 or less, and saving myself the stress is worth it. Looks like we'll do Mendenhall Glacier in Juneau, and the white pass train in Skagway. In Ketchikan, we'll just go walk around town a bit, if we want.
On the Cruise Critic boards, I found out more stuff I wanted to know, too.
Please let me know how you like the NCL Sun, and if possible, take photos