Ketchikan. Hop on a city bus south to Saxman for totem poles and a native crafts store. Also a city bus north to Totem Bight Park for more totems (of course). A city bus can also take you into residential areas above town and where you can get off at an overlook and walk down to town. If you ask nicely, the bus driver might go a bit out of the way to show you something different. Built on a steep hill, uphill and down involves lots of stairs. Note the school playgrounds under cover. It rains a lot.
Sitka. A city bus (or you can walk a bit) can take you out to Sheldon Jackson Museum of native artifacts. At the main bus stop in town, take a few minutes to look in the Performance Center. Nearby are a few galleries selling really lovely (and $$$) Alaskan art. Sitka was the capital during Russian days, so there are some historical walks and buildings in town.
Juneau. Mendenhall Glacier. State Historical Museum. City of Juneau Museum near the Legislature building has artifacts and info on the extensive area gold mining - even tunneling under town, Douglas Island and the Gastineau Channel as well as back in the mountains. Mount Roberts Tramway to mountain top. Whale watching tours good IF whales in area.
Victoria. If there is time and you like flowers, take a tour to Butchart Gardens. World class. Otherwise, Craigderrach Castle and Princess Hotel
Try to get away from the areas near the cruise ship docks - too many jewelry stores and t-shirt shops. Avoid the site-seeing "Duck" boats. Cost of excursions pushed by the cruise ship are higher. It is a shame that your time is limited in port. I often recommend a cruise using the Alaska State Ferry system so you can stay a night or 2 in ports.