Peloponnese in five days (Athens)

Kalispera Internations! What are the best spots along the seaside on South Peloponnese to see? I'm taking my parents there for a week, want them to fall in love with Ελλαδα the same ways as I did a couple of years ago :)
So far our route is: Athens - Corinth - Rio/AntiRio - Patra - Pirgos - Kyparissia - Methoni - Koroni - Kalamata - Mystras - Sparta - Monemvasia - Navplion - Epidavros - back to Athens. This is all Monday to Saturday, a lot of driving, secret mission is to find a place we can rent in winter for my sister to come for a couple of months with her little one.

Any tips on beautiful villages, family restaurants and places to stay on the seaside would be much appreciated!

Ευχαριστώ πολύ! :)