Even the ships that dock in Skagway have tours in Haines. They are a very short distance and boat ride from each other. Haines is a very small town formally used more as a military base.
The best tours in Haines all involve going to see wildlife. There are some great tours going back to see the eagles as well as possible sightings of moose and other wildlife.
I have not been on HAL in Alaska but have cruised Alaska many times. As I said the best tours in Haines will be to see wildlife. Seeing they are so close you may find some tours to Skagway also.