further to my post from a week or so ago, Andoni Merlin - who also manages the SL Planetarium Dome - has very kindly scripted two free shuttle services linking the SS Galaxy with the Linden mainland.
the SS Galaxy -> Avignon shuttle will whisk you to the Avignon Turtle Sanctuary and Wildlife Reserve (managed by Breandan Turas) in under ten minutes.
if you have eighteen minutes to spare, do consider taking the SS Galaxy -> Nautilus City shuttle, which traverses the length of Nautilus City and lands directly at the harbour.
you can board both blimp services from the public helipads abaft the Galaxy. if you wish to take a round trip, just stay onboard your blimp and it will start its return journey after a minute's wait at the Turtle Sanctuary or the Harbour respectively.