Just returned from Baltics cruise. Took the train from Warnamunde to Rostock. What a delightful day. Our friends went to Berlin and said it was a LONG day. About 11 hours round trip, by the time they got back to the ship. Rostock is a neat little town and the train drops you off right at the city square. However you must change trains to get into downtown Rostock.
While in St. Pete, do not miss the subways!! They are one of the wonders of the world. There is a ship excursion called Through the eyes of the Russian people. You will ride the subways and go to a large market in downtown and also go to a vodka tasting. Probably the best excursion we took. If you are interested email me and I will be glad to tell you what we did in each port. We only use tour guides in Russia.
Have a great cruise.