I'm a 'walk around the town' kind of person. In the ports I've been to from your list, Mykonos, Rhodes and Santorini are all walk around town ports. If you want to go to Oia while in Santorini, the boats right where you tender will take you there, then you can catch a bus back to Santorini once you have had a wander there (very easy). You will need a tour if you want to see Ephesus (highly recommended).