We are going to Alaska in May. Any ideas about the zip line in Icy Strait? Is the braking at end gentle enough for arthritic knees? Also, has anyone been on the semi submersible boat in Sitka. Was it worth it? Or any other suggestions for Sitka or any of the other ports. We already have a whale watching private tour scheduled for Juneau. Plan to ride railroad in Skagway. We've been to Alaska beore, but been long time. Now we're young retirees! Any help appreciated.