We did this two years ago when we were on the Ruby. I cannot recommend it enough. I was uneasy about the price of the excursion but it was absolutely so worth it.   Here's what happened.... We woke up at the crack of dawn all bleary eyed and got onto a little boat that pulled up next to the Ruby. The boat drove us up Tracy Arm towards Sawyer Glacier. After the boat pulled away from the Ruby the Ruby turned the other way. We went towards glaciers, the Ruby went back towards civilization.