Christos was a great host and even offered a ride from the airport for 24€. The apartment is a 7-10 minute walk to the metro, and just 3 stops away from the center of Athens. There is also a park 5 minute walk away if you want to do a bit of exercise in the morning. There are plenty of commercial options on the main road a block away, but also just 20 minutes away to the center of city for more food, shopping, and tourist attractions. The metro is very easy to use, and a 24 hour day pass is 4.50€ which you can buy at the ticket machine in the station.
The room is pretty simple, with a balcony and air conditioning. It was great for a short stay in Athens.