Kelly's apartment is a perfect little headquaeter for your visit to Berlin. Location is actually very good: you have great access to the circle line (41/42) that will land you directly to Prenzlauer Berg (the best), the TXL bus stop just 400 mts away (great line, use it instead of the turistic bus!), and near 2 subway (u-bahn) stations. Also: a enormous supermarket (Edeka) is just blocks away. Perfect if you want to buy supplies to cook your dinner (saving some money).
If you walk around there's the beautiful park Tiergarten with a tea house, and you can walk even to Ku-Damn if you are in the mood. If not, it's just a couple of u-bahn stops away.

Kelly is really attentive, she left little treats for us on top of the kitchen table, and also, she spent half an hour or more explaining us how to move around Berlin, with tons of great advise. She really goes the extra mile to ensure your experience is great, and smooth. She's really sweet! I recommend her apartment, I definitely will pick it again in my next trip to Berlin!