We were made to feel very welcome in Thelma's apartment in Athens. It was extremely clean and well appointed, and had a very modern feel. The AC was welcome as it was hot outside, and so we were able to get a very good nights sleep.
The apartment is only a short walk from the nearest metro stop, and from there it is a short journey into the centre of Athens. There is also a supermarket nearby that is big enough to provide anything you could need, which came in very handy. Thelma provided several maps and guides for things to do in Athens which were extremely useful! She also provided loads of useful instructions before we arrived via email, including detailed guides on how to get the apartment.
One thing I would suggest to all future guests is when you are using the metro make sure you validate your ticket! We weren't told to by the ticket seller and the fines are really hefty (though we thankfully avoided them).