We have been in that Port and our ship was docked 300 meters from the train station, we just walked over to the train and took it to Berlin for the day, 2 1/2 hour ride that was lovely. You could also go to Rostock only 20 min ride. You can take a tour with Viator to Sachsenhausen Concentration Camp Memorial and Berlin’s Third Reich sights . They guarantee to have you back to your ship. I have used them and would recommend them. I would also look at this website Whatsinport.com I have not been to that concentration camp on our trip we went to one in Poland.