I am offering a studio, part of my flat, on the 5th floor (bathroom, no kitchen, own entrance, no lift). The room is quiet and has a great view of the Fernsehturm.
The flat is opposite Volkspark Friedrichshain and located between Prenzlauer Berg and Friedrichshain. The access to public transportation is excellent. Alexanderplatz can be reached in less than 10 minutes.
I moved to Berlin several years ago and would be happy to share my own tips for your trip in Berlin.