The apartment is very strategically located and one can just walk to most of the main attractions of Istanbul. While Okan was unable to meet us, we were met at arrival by a nicely dressed and helpful staff.
Just to manage expectations, the Sultanahmet parts of Istanbul is very hilly. Strongly recommend to get a shuttle or taxi for arriving and departing the apartment. Unless you are very, very used to walking with luggage up and down hills I would not choose public transport.