Hi there, presuming that the ship docks 'round the back' of Venice - and of course actually docks in Venice & not their alternative in Trieste which is miles away - then the easiest way is to get a day pass for the Vaporetto's (waterbuses)
From the cruise ship terminal walk to the train station. There you will find the Vaporetto. If you want to walk there (and see the sights along the way) walk through the train station and head left along the main street.
If you generally just follow other people you will eventually get to St Marks Square. Walking at fast (New York) pace it will take about 1/2 hour, a slow walk in an hour.
There will be a few places where you can take a few different short walkways, but they generally lead to the same place - just make sure you are in a flow of fast walking people - then you know you are on the main walkway through the city.
I am the editor, but I also speculate, ask questions and play devil's advocate. I reserve the right to change my mind.
Indeed if you are healthy and a good walker you can follow Paul's plan and walk around Venice. It is not a large place and the locals are good walkers.
BUT -- if you are like me and NOT able to walk long distances or climb lots of stairs, or have seniors or little kids in your party, then it is different. I sincerely recommend in that case getting a good guide company to take care of all the arrangements for you. It was very nice for us to be at a crowded vaporetto stop and see our guide pulling up in our private water taxi! Of course this is expensive - Venice is expensive - but it makes the city so much more enjoyable!
You could also take a vaporetto there, and walk back if you prefer. A one-way vaporetto ride is 6.50 euros per person. You want vaporetto #1 as that one goes a little faster. You would board at Piazzale Roma, which is only a peoplemover (monorail type) ride away for 1 euro. An all day vaporetto pass is 16 euros if you really want to limit walking. The Doge's Palace is the really decorated pink building in Piazza San Marco, and the visiter's entrance is closest to the water. It is amazing, but buy a guide book or rent an audio guide as there is so much interesting history and art here.
How would you get from the cruise ship terminal to Doges Palace in San Marco?
When I was in Venice several years ago, there was a tender service from the ship's pier a location on the waterfront that was right near the Palazzo Ducale (Doge's Palace). The Palazzo Ducale faces a pedestrian walk perpendicular to the waterfront that leads to the Piazza San Marco (St. Mark's Plaza). The Basilica San Marco (St. Mark's Basilica), the cathedral church of the (Roman Catholic) Patriarch of Venice, is on the far side of the Palazzo Ducale facing the piazza.
I was in Venice last summer but I just read that there is a new People Mover from the cruise port to Piazzale Roma where there is a vaporetto station.
You can buy a vaporetto day pass; we did a whole round just to get a feel for Venice but you can also take a more direct waterbus. If you walk, there will be signs for destinations like Rialto and Piazza San Marco.
The Doges Palace was very interesting, lots of walking, climbing but you see the prison and the Bridge of Sighs.
If you are mobile, then a gentle stroll to Piazzale Roma is a good way to start the day without feeling you have been 'ripped off'.
Alan & Katrina[/QUOTE]
EVERYTHING in Venice is hugely expensive. It is essentially impossible to get "ripped off" any more than the standard prices do!
As we were leaving, we had private transfer booked to the bus station for the airport. From the gondola to the bus was about 20 yards. A porter took our bags across for us and then demanded 5 Euros PER BAG!