Olga is the best host i've ever met. She is helpful and hospitable like your best friend. The room is bright and it has a balcony. It is very convinient for drinking a cup of tea with a cigaret, reading book or just watching into the distance.
The apartment is located in the district called Stavrupolis. It is about 3 km to city center, but the weather is mostly sunny in Thessaloniki and you could walk this destination. There are a lot of cafes and supermarkets close to Olga's house and you'll find everything you need around.
Olga's suggestion is better then google. Listen to Olga and everything will be fine.