We did a Greece/Turkey cruise last year, not DCL, and had stops in Mykonos and Ephesus/Kudasai. Ephesus is amazing, a highlight of the whole trip. IMO if you hit that port but don't see the ruins site you are really missing out. It's so grand, even the kids will really get something out of it. Mykonos is fun to just walk around the winding streets, shop, etc... It will give a good taste of a greek village.