I came to visit Berlin with my younger son. Prenzlauerberg was a lovely area to stay in and Kerstin's place was wonderful, peaceful and near to easy transport. Lovely cafes nearby, Cafe Butter and Anna Blume. Great places to eat nearby - I can recommend Ordequelle. Lila's bike hire just down the next street which was the cheapest and with great service, we cycled everywhere.
Kerstin met us and showed us how everything worked and was a great host, willing to help if needed. We will definitely go back if we revisit Berlin which we would love to do!