We arrived by train and took the “water bus” (ticket fare required) to and from our hotel. Speaking with others, there is a further stop where one then makes transfer to Marco Polo. I read this comment online: “They (taxis) can be expensive (a ride from Venice Marco Polo Airport can easily set you back 100 euros or more), but because water taxis hold more passengers than a land taxi does, the cost per person isn't too bad if you can split the fare with friends or a small group.Feb 17, 2010” I don’t know hours of operation, especially at 4 in the morning. Why not contact the hotel? I suggest reading about transportation options at the online italyogue

I would suggest a taxi. You could walk but I always find it awkward when you have luggage to tend with. At the hotel you will get a very helpful map of the sights in Victoria and you can then explore the city without the hassle of bags/cases.