well, I am not greek! I am from bosnia and I am a teacher too, but as I lived in UK, italy, greece after my graduating, I did not teach for long. so I can tell you more geography!
there are some cooperatives in greece where you can buy good food, but living on an island it would be too expensive to to go to the mainland to by it.
for your geography information, I live in salamina, the closest island to peiraius, just 2 miles to the mainland. and even closer to megara, small town on the way from athens to peloponnese.
liliana
My wife and I and 3 of our sons spent a year in Volos about 20 years ago.
