Advice on Peloponnese Itinerary

Hello all!

My family (4 of us, two kids 11 and 13) will be visiting Greece for the first time in June, for 20 days. The first week will be spent on a boat in the Cyclades with another family. Then we plan on flying back to Athens, renting a car, and spending 5 days in the Peloponnese. Our focus will be on ancient history, charming old villages, interesting architecture, and lovely open-air tavernas for meals. I have one kid who can get carsick, so we try to keep our drives relatively short. We also try not to do many one-night stopovers.

Our tentative itinerary is:

• 2 nights in Nafplion, with trips to Mycenae and Epidauros.
• 1 night on the western Mani peninsula, likely Areopolis, after exploring some of the Mani by car (which villages should we stop at, between Nafplion and Areopolis?)
• 2 nights in an as-yet determined village that is a decent base to visit both ancient Messene and Ancient Olympia, ideally within 2 hrs of both sites. Looking for something really charming, more of a destination-type village rather than just convenience. Open to a harbor village or a mountain village. Walkable, friendly, with lots of ambience and good food!

Any ideas for that last location? I've looked at Pylos, Petalidi, Stemnitsa, Koroni, Katakolo. I haven't ruled any of those out yet. I'm not super interested in Kalamata because we will be in Athens at the end of our trip and I'd rather stick with charming village vibes in the Peloponnese. Is that a mistake?

We will spend 4 nights in Athens before flying home.

Thanks in advance!