restaurants in Istanbul, Nauplia and Athens
My experiences in all three places are too far back to be useful (though if O Platanos, with its spreading plane tree, is still there in the Plaka you might check it out -- a delightful place for an outdoor meal), but I sure hope Nafplio (as they call it when not writing maps) has acquired better eateries in the intervening years. In Argos I had the best spaghetti carbonara of my life, but there's no other reason to visit the place.
Unless Istanbul has gone badly downhill since I was there in '91, you'd have to work hard to eat poorly. Any little hole-in-the-wall we stopped into had fantastic vegetable-and-meat stews and other bits of the amazing Ottoman cuisine, so much richer than is generally realized here. And the baklava! Enjoy.