Thanks for your replies. We've found a Viator tour that will pick up from the pier. Our only concern is making it back in time for sailing. We've decided to pack overnight clothes in our backpacks and if worst comes to worst and we don't make it back in time, we'll have to overnight and catch the ship at the next port. It may be a little expensive at that point but we don't know when we might have the opportunity again. A little adventure is good for the soul. :-)