The photos don't make it justice: it's cosy and extremely clean. Eleni is an amazing host, showed us every way around town and made our stay much nicer, giving us local tips.
It's 15-20 mins walking downhill to some of the main attractions in Athens, the house might not be in the City Centre but the transport will make it easier to travel around.
My personal advice: Take the 5-day ticket for public transport and use it as much as possible, you can use it in buses, metro, tram and everything else except Airport transfer (as far or more than you think you can go with public transportation).