Peloponnese peninsula

I would go 60km 1hr from Nafplio to Kapsia Cave via road E 65 and then on to Olympia a scenic drive

Leave E65 when signposted "Ancient Olympia" and follow Road EO111 and EO74 to Olympia
To get to the cave turn right 2km at the Gas station when entering the little village of Kapsia
Its 9km from the exit of E65 direction Ancient Olympia

Just one stop on the way

Drive on 50 km 1hr from there to Langadia a mountain village on EO 74 with Restaurants and Kafenions

It is a 60km 1,5hrs scenic drive to Olympia from there

Nafplio is the gateway to the Peloponnese when coming from Athens. Olympia is on the opposite side of the peninsula on the west coast. Will you be driving directly from one to the other via the shortest route or do you want to visit the Peloponnese?

There are hundreds of places to see: archaeological sites, villages, monasteries, hikes, beaches, etc.

How many nights have you planned? Logically, if you want to visit the Peloponnese and continue to Delphi, I assume, via Patras, you should spend most of your travel time between the places you mention (Olympia and Delphi are only archaeological sites, where you won't spend more than half a day).

Below is a map with a partial list.

https://www.google.com/maps/d/edit?mid=1kFRC74X_9PHcQ_3FNY62F_tURD34mLs&usp=sharing

Its another 3 hrs drive from Olympia to Delphi

See the towns of Pyrgos 20km and Amalias 40km on the way to Patras

Near Amalias 5km there is a nice sea side village Kourouta with a sandy beach
Or see ancient Elis near Amalias 15km

Cross the sea via bridge north of Patras direction Nafpaktos to Delphi 120km 2hrs

We will spend two nights in Nafpilio, two nights in Olympia and two Nights in Delphi which should be enough time to see mainly archeological sites along the way. A visit to a beach could be a nice diversion. Thanks.

I have been to Nafplio and Delphi. I would suggest you spend 3 nights in Nafplio and 1 in Delphi. There is much more to see in and near Nafplio than Delphi.