We had a blast ziplining in Ketchikan with Kawanti Adventures. Branch and Amy were our guides and they made it relaxed and fun, and put our fears at ease, as we had never been ziplining before.
If you are afraid to try ziplining because of the heights, I would say this is a great place to overcome your fears, because the dense tree cover obscures how high you're up and is also very beautiful. Would definitely recommend!