Nelly’s nephew Nico was waiting for us outside of the apartment and he carried our luggage for four flats of stairs (there is no elevator). He also kept in touch with us during our stay and was available any time for any questions we had. He even gave us a ride to the supermarket.
You can walk from the studio to any place in the city center, it was perfectly clean when we arrived (just like in the picture). We would definitely come back if we come to Athens!