By metro + bus #052
Its very easy to travel between the main bus station in Athens called Kifisos KTEL and my apartment. You just have to go to Eleonas metro station (blue line). From there bus #052 connects metro station with Kifisos KTEL bus station. Bus #052 is a circle line with only 2 stops. Eleonas Metro station and Kifisos KTEL bus station.
In metro blue line there are trains every 3-6 minutes. Travel time between Holargos metro station and Eleonas metro station is 18 minutes (10 stops). But Total time from apartment to Kifisos KTEL bus station is around 50 minutes. More information about first and last trains you can find here. Tickets cost 1.20€ and are valid for 90 minutes. With this ticket you can go anyware except airport. More information about tickets here.
From Kifisos KTEL bus station depart most buses to mainland destinations in Greeece and also to Ionian Islands.
Read more: My apartment is located in a strategic location to access Airport, Port, Bus and Railway stations