In Ketchikan, if you mean the lumberjack's show, we've done it. You can do this on your own as it's only a block from the ship. .
Juneau, you can take the very cheap $ local and empty bus to the glacier. We've taken the ship's tour 5 times and felt rushed so the last time we took the local bus.
Skagway, if you take the train ride, make sure you sit on the left side going up. The sights are on the left. We've also done the gold dredge. It's mostly about how the device operated. Afterwards you have an opportunity to pan for preplanted flakes of gold. It was enjoyable.
Victoria, you can hire a cab to the gardens and they will wait for you. The rest of the city you can do on your own. The last few times, I walked from Ogden Point(Pier) to town center. (20 minute walk)
Sitka, you can definitely do it on your own. The raptor center is a little further out.