Kadıköy is a open, cosmopolitan and safe part of Istanbul. It is close to ferries, metrobus, metro and bus station so it is well connected. With my flatmate Ilknur we live in an appartment and are renting one spacious room.
I do not mind if you smoke in the room, but generally we smoke in the kitchen. No noise after 22h. It is not a party flat. Please do not enter with shoes.