GG, A very long shot, but have you considered flying on to Crete? I know you only have 4 nights, so you may not have enough time.

I spent three glorious weeks on Crete in 1983. After 5 days in Athens (and a three day/two night bus trip from France), we took a cheapie Olympic flight to Herakleon.

I spent my time hiking, eating, drinking and visiting some incredible archaeological sites. People very nice, food and drink and lodging simple but good and reasonable.

Just an idea. I have no other ideas for Athens or its environs. Have a great time.