I just came back from turkey- greece. It was wonderful.
you can go to Istanbul and from there go to Izmir(or they will take you to Izmir). from Izmir get the ship and go to greece. You will see Athens, Myknos, Rhodos, Girit, Kos. 1 day each. if you are interested i can give you agency email address as they orginised this trip for me. write me private if you are interested in. And you don't need Shengen visa to visit Greece if you use this agency....