Here are some infos about the ferry connections to and from Travemünde.
TT Line connects Travemünde and Trelleborg in Sweden. The Service specifically targets travellers besides carrying cargo.
The journey takes 7 hours and the price is € 30 for a pedestrian.
Finnlines operates a routhe between Travemünde and Malmö (Sweden) and one between Travemünde and Helsinki (Finnland).
It is not possible to use the Malmö Line as a pedestrian. It is possible however to use it as a cyclist (€27).
The passages to Helsinki are not cheap and you have to take a cabin however - remembet that the journey to Finnland is 36 hours long (Hansa class ship/ 27 hours on a Star class ship - more expensive ). The Finnlines ticket price always includes all meals on board.
Check out these websites for more information:
http://www.ferrycenter.fi (Finnlines)
http://www.ttlinie.com (TT Linie)
The other ships calling at Travemünde's port are freighters only it is possible to book passage on some of them but I have no experience with that.
The port is easily accessible via the railway station "Lübeck Travemünde Skandinavienkai". Trains call here at least once every hour connecting it to Lübeck Hauptbahnhof (Central station) and from there to Germany's long distace rail network.
