Family Trip to Peloponnese in March - Which Towns?

I tweaked my own itinerary in a similar way. I'm in Greece right now, for 3 weeks. I originally booked an overnight in Monemvasia, then decided it's too out-of-the-way, and there are so many other sights that are more central. From Nafplio, you can do a day trip to Mystras or Olympia. I'm doing 5 nights on the Peleponnese: 2 nights in Gythio (with day trip to Limeni and Kardamyli) and 3 nights in Nafplio, then returning my car to Athens airport. (Athens Car Rental - ACR - will pick up your car at the Sofitel.)

You can go to Hydra even in March, but I'm not sure staying there more than one night would be a good idea. (by the way why are you going to Hydra? )

If you take the ferry to Hydra in the morning you will have time to visit the island during the day. And to my knowledge the ferry to Ermioni leaves from the port of Piraeus in the morning and is not in Hydra until mid-afternoon, so you will still have time on day 5 before leaving Hydra for Ermioni.

A good thing to do in March is to check the weather forecast before heading to Hydra.

https://www.meteo.gr/cf-en.cfm?city_id=133

Ferries can be canceled.with a wind from 8 to 9 Bf and above, this means that the ferries to Emioni will not arrive in Hydra.
which could change all your plans for the rest of your trip.

Thanks for the replies! Re why hydra? We like small car free towns and islands and Rick recommends it. But I am wondering if it’s worth the risk and effort in March. Maybe we should skip it and do either Monmvasia and mystras or Olympia and the mountains? Any recommendations?

TOo many people automatically say, Rick recommends it, and they go. Rick doesn't really like the Greek Isles (I don't know why) and doesn't write guide books a bout them or do trips to them. He adds Hydra at the end of his Mainland trips, for pepole who want to say they visited a Greek Isle. Never mind that it has almost no beaches available for summer visitors (you mainly jump off rocks) and has very little to "explore" in terms of archeology or drmatic landscapes, and you have to hike everywhere, which is not a treat in winter. Just to say, don't blindly take his recommend, do some investigating yourself

If you like "car-free towns" ... I can name half-a dozen islands with villages where cars are very inconspicuous and not used on most small lanes: Antiparos, Serifos, Amorgos, SIfnos, Kea, Kythnos, Chios, Patmos... that's for a start. And 2 islands MUCH closer to Athens than Hydra - Aegina and Angistri.