The Peloponnese is small, and all destinations are close to eachother. The most time consuming drive I mentioned is Nauplion to Monemvasia which is 3 hours, the rest drives are just 1 hour or so. So I don't think it's rushed at all, but adding a few days surely won't hurt you. Also consider that many of these towns are small and can be seen in just 1 day. So adding an extra day to a small town might be a bit too much, you would prefer to be in your car exploring the countryside or some neighboring villages and towns.

So for the days, consider:
-Drives are short.
-Towns are small and can be seen in a few hours.

Now, if I were you I would not add an extra day to a destnation. I would add a new destination, specifically Delphi. The ancient Oracle of Delphi is not in the Peloponnese but it is on your route for back to Athens following the northern route.

These 2 day would go like that:
Once you see Ancient Olympia and the Archaeological Museum, drive straight to Galaxidi. Spend your night in the beautiful little town. Wake up early you will do 2 stops. Your first stop will be Delphi (UNESCO), the Center of the World according to the ancient Greeks and one of the holiest sites of Antiquity. The Oracle of Delphi was the supreme oracle of Antiquity, Generals, Kings and Roman Emperors visited it frequently to hear the word of God Apollo through the mouth of high priestess Pythia. And don't forget to visit the museum, exceptional building and artifacts considered one of the top of Greek Museums.
Your second stop is Hosios Loukas Monastery (UNESCO) a grand imperial monastery of the Byzantine era. It's a masterpiece containing mosaics, frescoes, icons and is sculpted by the artisans from the Imperial Academy of Constantinople. It's a Byzantine masterpiece.

A simpler version of the updated Itinerary, so that you can Google it easier:

DAY 1
-Ancient Corinth
-Acrocorinth
-Ancient Nemea
NAUPLION

DAY 2
NAUPLION

DAY 3
-Ancient Mycenae (UNESCO)
-Epidaurus Theater (UNESCO)
NAUPLION

DAY 4
-Ancient Sparta
-Archaeological Museum of Sparta
-Mystras (UNESCO)
MONEMVASIA

DAY 5
MONEMVASIA

DAY 6
-Simos Beach in Elafonisos
MONEMVASIA

DAY 7
-Gytheion
AREOPOLIS

DAY 8
AREOPOLIS

DAY 9
-Diros Caves
-Vatheia
-Cape Tainaron
AREOPOLIS

DAY 10
-Kalamata
-Polilimnio Waterfalls
PYLOS

DAY 11
-Methoni Castle
-Voidokilia Beach
PYLOS

DAY 12
-Ancient Messene
-Temple of Apollo Epicurius (UNESCO)
STEMNITSA

DAY 13
-Dimitsana
STEMNITSA

DAY 14
-Ancient Olympia (UNESCO)
-Archaeological Museum of Olympia
GALAXIDI

DAY 15
-Ancient Delphi (UNESCO)
-Delphi Museum
-Hosios Loukas Monastery (UNESCO)
GALAXIDI

DAY 16
Return to Athens.



I hope that helped

Hi air balloon
I have nothing to say.
You already told me to move on on another thread.
Now you do the same with Kja who is one of the sweetest regulars on this forum.
I wish you a nice holiday.

Ps : I didn't say anything snarky or disagreeable I hope ?
I didn't offend you ?

Please tell me if I did - I don't want to take your prerogatives.

Wow, now I want to go to the Peloponnese. Petros and stan, thanks so much for sharing your ideas, itineraries and photos.

What a fantastic detailed plan, PetrosB3. Thank you so very much. It really does help and makes us want to leave tomorrow!!

On another note, I just want to say that almost everyone here on Fodor's is so helpful and nice, but there is always, as in life, those few who feel the need to not offer advice but to just be snarky and judgemental. kja and whathello are two posters who have have done just that on this post and another one of my posts. If help is something they did not want to offer, I simply told them to move on. I am sure they can find other posts that may interest them more. Nothing offensive about that.

Andrea

Air balloons are these small things made of rubber that get inflated so they can go higher. No ?
Good choice of avatar.

I can't tell for kja who is a gentle woman but there are a lot of people like me or worse in Europe. Try to be nice and smile when you communicate.

How was your trip to Spain last August, Andrea?

@ PetrosB3 -- what an awesome itinerary! I've taken note and offer my thanks.

@ Whathello -- thanks. :-)

@ AirBalloon -- I am sorry that you have not found my comments helpful, as that has been my intention.

kja: no problem. Let's all (almost all, actually) of us just try and learn from each other's travel experiences and help each other out when we can.

Andrea

Almost is fine by me.
Very fine.

Hi everyone,

We are now going over the finer points of our trip. Very excited!!

Thanks again to everyone who helped us with our plans, especially PetrosB3 with the detailed itinerary.

Andrea