When we went to Alaska a few years ago on
DCL, there weren't any options to do that through Disney, but two friends recommended Above & Beyond Alaska. We did a kayak tour out to Mendenhall Glacier and got to walk on it and climb it. They provided everything and it was an amazing adventure for us. Our friends did a hike to the glacier instead of the kayaking and also enjoyed it. Because of the personal recommendations, I didn't look carefully to see if there were other tour companies that provided similar opportunities, so hopefully others will chime in here. We really did not want to go by air and this worked well for us. We loved our DCL Alaska cruise!