A great place close to the T1 line in a cool local quiet neighborhood. The T1 tram will take you directly to Eminönü where you can see a lot of historic sites. Taksim is about 10 minute walk slightly uphill, and Karakoy is about a 10 minute walk downhill. A small desk to work from if you have a laptop with good internet. I stayed at Mehmets place for almost 1 month. Mehmet is a very nice accommodating host.
Sidenote: the neighborhood Cihangir is a hilly part of the city, so if you have heavy luggage you may want to take a taxi there.