Has been to Bucharest to Budapest by boat?

My friend and I are planning a trip to Europe this summer, we fly Buda, Pest and Warsaw after 2 weeks. We intend to travel to Romania in Warsaw by train, but I found a boat on the Danube. Can anyone tell me how this is possible taking into account we're in a pretty tight budget? Any experiance / advice on this part of the world is also welcome! Yes, it is a fiction! And I'm sure that even if it was true that I can be OK, as I have been dam before hand!

Check out this may help: http://www.mahartpassnave.hu/

Traveling By Train in Europe : How to Book Train Travel From Prague to Vienna

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