Athens/Napflio/Delphi 8.5 days late Apr/early May advice needed

This is a feasible plan although indeed with a lot of driving between Nafplio and Delphi, but I often see worse. :)

You did not give your exact dates but note that on May 1st all museums and sites are closed. So do not plan a visit on that day.

There are also major demonstrations on May 1st in Athens around Syntagma Square with possible metro station closures and bus line interruptions.

About the days in Athens:

Apart from the National Archaeological Museum, everything you want to do and see is concentrated in a fairly small and largely pedestrian area, what you have planned for the mornings and afternoons will probably change as the hours go by, but it is not very important.

For example, walking around the small Anafiotika district will not take you all afternoon, just an hour or two max
Monastiraki Square is just a square, but from there you can go for a stroll in the flea market and in the Psyri district which are nearby.

The Temple of Olympian Zeus and Arch of Hadrian are next to each other, what you can do next is to cross the National Garden and go to the Panathinaikon Stadium

Here is a map with the location of the main "attractions" of Athens;

https://www.google.com/maps/d/edit?mid=1OhGNGU1LUEgwFTul8u4YEe_tijF8Hqs&usp=sharing

On DAY 4 you drive to Cape Sounion and then back to Athens. Think carefully about what you will do with the car in Athens before leaving the next day for Nafplio. A car in Athens, even for one night, is a source of driving and parking problems.

Just for information here is how to enter the Anafiotika neighborhood:

Go to Lisiou street. At the intersection of Lisiou and Mnisikleous, take Mnisikleous, go up the stairs. There are some nice restaurants and bars all along the alley.

Once you reach the top of the alley it becomes quieter, turn left (Prytaneiou street).

After a few meters you will see a church on the left and a small passage with steps on the right. Go up the steps in this passage and continue straight between the murals.

That's it, you are in Anafiotika.

See here:
https://maps.app.goo.gl/mEFiq5z2f615rRdw7

You can exit from the other side (towards the Roman Agora), see here:

https://maps.app.goo.gl/DH5wbFozJY1hSSh79

Of course it is possible to swap entrance & exit if you prefer.

Thank you to both of these posted replies! I has no idea about May 1, (was our drive to Napflio, so will look at changing the corinth/mycenae visit). I have heard about parking issues in Athens, but didn't know how else to manage this. Like most European cities, I assume accommodation with parking is far from where we should be staying in Athens? Any accommodation suggestions? (Area or specific place) I also heard that people sometimes park at the airport and then metro it back I to athens, which is certainly what we would be doing upon arrival, before any car rental. Is this advised?

To visit Athens the best areas to stay are around the Acropolis in the neighborhoods of Plaka or Makrigianni, or North of Monastiraki square or possibly a little further in the neighborhoods of Koukaki or Kolonaki. Everything you want to see and do will be accessible in less than 20 minutes walk.
We regularly spend a few days in Athens but we stay in Airbnbs and sometimes not in the tourist center, so I don't have a hotel to suggest but other forum members who have stayed in hotels could give you some recommendations, or you can find them by browsing the forum posts.

In any case, don't expect to find a parking space in the streets of central Athens, it's mission impossible and IMO there is little chance that the hotel you will find has parking. You will have to ask.
Otherwise there are some paid and guarded car parks, see for example this link:

https://www.parkaround.com/

If you do not want to struggle with a car the other option would be to go to Cape Sourion by public bus or Hop on - Hop Off bus or any other organized daytrip.

Here is an example:

https://www.sightsofathens.gr/

(you will find the same but more expensive on Get Your Guide or other third party resellers)

Also take into account what I said about the demonstrations in Athens on May 1st, if you want to leave Athens for Nafplio that day leave early otherwise you could have some issues with the traffic that will be interrupted on few avenues and streets in the city center.

What you can conclude from this and what everyone will tell you is that a car is not only useless in Athens, it will also cause you a lot of problems

Thank you! Yes, we will avoid a car in Athens. Still trying to work out what a trip to Cape Sounion will look like, as it had been our hope to take our time on the coastal highway, stopping along the way, and a bus or group trip won't do that.
Thank you also for accommodation info. Like you, we don't usually do hotels, and are looking for a vrbo/airbnb outside the downtown, but on/near metro. It's always so lovely to be in a neighborhood instead of the tourist area. Are there neighborhoods you would recommend in that case?
So, we may switch the order of napflio and delphi in order to be travelling our long distance on may 1, since no museums will be open. Collecting a rental car on that date may prove difficult though. Perhaps we'll leave athens a day early and put that day on at the end. I'm really wishing we had another day or two!

It's up to you to see how you can optimize your stay.
Delphi + Nafplio + Athens in 8 days is the limit of what is reasonably feasible to enjoy the trip without rushing from one place to another..

There are about 12,000 Airbnbs in Athens.
Many are managed by real estate agents, but if you prefer to stay in an Airbnb run by a private individual rather than a professional, you should not use the US version of the website.
Since European law requires websites to specify whether they are managed by a professional or a private individual, if you select the English / Ireland version you will see the mention "business" or "individual" in the accommodation list.

If you are only 2 or 3 people I can send you a list of Airbnbs that can match what you are looking for. (in private message, - I don't put it in public forum anymore, I don't know if it's a coincidence but I noticed that it makes them too popular and less available).

Thank you! You have been incredibly helpful (and I notice you are active in your help of others' questions as well - you should be receiving commissions, lol!). Anything you send privately for airbnb is much appreciated - there will be three of us. I have checked some vrbo stays in Koukaki and Kolonaki based on your input and sent off parking enquiries to them. Based on some other forum reading I have been doing, I am also looking at the possibility of picking up the rental car immediately upon arrival at the airport (Apr 26 at noonish) and heading to Delphi first for 2 nights, then Napflio for two or three), then ending with Athens for the remaining 3 - 4, including the day trip to Cape Sounion. It still doesn't solve the issue of what transportation we use to Cape Sounion, since I believe it would be too far to go there from Napflio, enjoy the coastal drive and temple, drop rental off and check into accommodation. It also depends on where May 1 and weekends fall in that itinerary (I thought to try to avoid Athens museums on weekends, but perhaps it doesn't matter as much in the beginning of May), but that revised itinerary would keep Athens as one set of dates/accommodation rather than both at the beginning and the end (fly out May 5 1pmish), if that matters. Further research to do!

You are right, I could ask for a commission !
but my best commission is to know that I have provided some help :))

If you feel that you are able to drive about 2h30 after a long flight you indeed have also the option to go to Delphi as soon as you arrive at Athens airport. It's 80% on highway then road without particular difficulty.

And it solve the inconvenience of having a car in Athens by returning the car (which you will no longer need) on your first day in Athens. The itinerary would then be like this

Athens Airport car pickup → Delphi → Nafplio → Cape Sounion → Athens car return / Athens visit..

It's about 2h45 drive from Nafplio to Cape Sounion, If you get up early enough you can be there around noon. and after you can drive to Athens via the coast and return the car..

I will send you information about the Airbnbs in a private message.

I have been to Delphi, but not to Cape Sounion. So I looked up the Cape. To me it looks much better as a site than Delphi. Delphi is small and crowded. In April the upper part was not open. You pay for the whole site but miss the better part. You can see the sea, but it is in the distance and that's it. The oracle of Delphi is not really a thing you can see. You have to learn about it and then imagine it when you are there. The ruins are not that spectacular. It's the setting. But Cape Sounion looks better to me
Knowing what I know now and applying it to your trip I would nix Delphi and use that drive time and days time to extend your stay in the Napflio area.

Thanks to both of you for your suggestions. I will look forward to the private message regarding Athens airbnb's :)

A few years ago we had a wonderful stay in Nafplio at the Aetoma. I quick scan of recent reviews notes the same positives we recall: spacious, comfortable room ( ours had a large balcony), gigantic breakfast, excellent location and the most gracious hosts ever. We were served cake and coffee when we checked in. When we checked out we were given directions to the bus for our return trip to Athens. As we waited, Pan’s son appeared…he had been sent to be sure we found our way!

Nafplio is lovely, great sights nearby and the Aetoma combined for a memorable visit. Safe travels.