I got the ferry from Tallinn to Helsinki, there are a number of these every day, cost 58 euro for me and the bike. The journey takes 2 hours and you get off right in the middle of the city. This is the website http://www.tallinksilja.com/en/web/int/book-a-cruise you can book through other websites but they are usually more expensive.
Helsinki big modern and expensive city with a population of nearly 1.4 million. Not sure what happened to the Medieval old town though there was lots of Scandinavian style. There is one metro line and trams and buses, a single ride costs 2.20 euro or you can buy an unlimited ticket for 1, 2,3,4,5,6 or 7 days very flexible and the only city with this option, usually its 3 or 7 days. Most people speak good English and signs have an English version as well so its a very easy city to navigate.
From Helsinki I travelled by ferry to Travemunde in Germany, cost 125 euro for me and 82 euro for the bike. The journey takes 27 hours, board at Helsinki 1730 and arrive at Travemunde the following day at 2100 hrs, which meant I had to spend the night there and leave for Holland the next day.
The end of my bike trip, 27 countries, 118 days
12,501 km, 536 litres of petrol costing 855 euro