I just got to say it, but I will try and be nice about it.
You will see some beautiful scenery, and some wildlife. But you do not begin to see Alaska down there. It will be rush, rush, rush from the time you leave the boat till you return. All the toursw even the ones that come up here to the Interior is rush, rush, rush. Friends that have taken the tours have hated it after they got back, due to the rushed attatude of the tour companies. There is a reason the rest of Alaska calls that area the Seattle Suberbs. First the scenery is not all that differant from what you can see on the Oregon and Washington Coast. Climate is about the same as well, rainforest. And the people there have far more in common with Seattle than with the rest of Alaska. Even our Capital Jeanu prefers to deal with Seattle than the Rest of Alaska. Tourisium has taken over there, and almost everything is staged to make an impression. To get the tourist dollers. It is even beginning to happen around Denali Park. Everything geared around the Tourist doller.
If you really want to see Alaska, stay off the tours and just come up here on your own. Get a copy of the Mile Post (You can get a copy at your local bookstore) and do a little homework and decide what you want to see. Mt Mckinnley, the Yukon River, The cities of Fairbanks, Seward, Valdez, Homer, Whittier, Kenai, and Anchorage. Fish the Russian River, and the Kenai. Ride the train from Anchorage to Seward, then back. Fish for Kings right there in Down Town Anchorage in Ship Creek. Take a Flight Seeing tour and see thousands of Caribou out on the Tundra. See Moose running around town in any town or city. You can rent a car or a motorhome. Take your time, see what you want to on your schedule.
An old high school buddy came up here a few years ago. I convinced him to bring his wife and come to Fairbanks two weeks early. My wife and I took them to the places we thought they would like to see. We drove to the Artic Circle, and the Yukon River. We were on the Haul Road, Dalton highway, (the road you see on Ice Road Truckers). We also took them to Mt McKinnley, and on to Anchorage. Then we went to Seward by train. Then they took a Cruise from Anchorage to Seattle. They say the best part of their vacation was before they got on the boat. The scenery was nice, but it was too rushed and too controlled.