Not really sure how far you will be traveling from the hotel to the pier. You may want to check with your travel agent and see if you can just get the transfers and how much they are. It may not even work depending on what hotel you are staying at, but its worth checking into. I don't know about that train ride???
Good luck and it sure does sound like quite a savings, but you want to make sure you make it to the pier on time, etc.