My family and I had a great stay with Sylvia. She has a large apartment with a great space outside on the balcony. The apartment was very close to several pockets of cool bars, restaurants and her recommendation of Seychelles around the corner was perfect - a great local place on the square with good food and ambiance!
Also within walking distance - maybe 20 min to the center of town through Psiri - look for the street Agion Anargyron and browse the street around there...!
We stayed during some hot days in September, so those that are used to A/C might miss this, but she does provide a large fan and considering the very reasonable price point and Sylvia's caring and charming personality (that we unfortunately only saw at check-in as we were also out a lot and Sylvia was kind enough to leave her room for my father one night:) - I would say that staying with Sylvia is great base for exploring Athens off the beaten track and close enough to the main sites and very good value for money! I would return any time and hope for sharing a drink or meal with Sylvia next time :)!