We are just about to head to Warnemunde / Berlin on the H A L / Westerdam July 10th (a Saturday). It sounds like you have a wealth of experience of this port and its connections to Berlin. I have found that even RailEurope were finding it hard to confirm details of ticketing on Deutsche Bahn.
Which Berlin Station should we head for to do the scenic bus tour?
Which station in Warnemunde (or should we take your advice and head out to Rostock by cab?)
Are we better off staying in Rostock?
Are we better off staying on the ship!!!!
All advice gratefully received