Not sure how many planes Michele (Island Wings) has for Ketchikan, because we have filled all the Bearwatching spots already deposited via Maskai's group.
In 2001, The Wings of Alaska Booth on the pier, next to the Dock did the excursions to the Taku Glacier Lodge for RSSC. Some people booked with RSSC, as we did, but there were several ships in Juneau and some people were able to walk up and buy tickets then and there.
When we've just walked off the ship with nothing planned, we have not done more than hire a taxi for a taxi tour. We had the most wonderful driver in Bermuda, but usually if we haven't used a private guide that someone we trust has recommended, then we book through RSSC. They fairly price their excursions and you have the extra benefit of making sure that they wait for your return if you were late due to traffic etc.