I want to spend my first full day at Delphi. I don’t want a guided
tour.
To get to Delphi, take the bus from the KTEL Fokidas station (Terminal B), located here:
https://maps.app.goo.gl/VtUp7MqRkDkffNgV6
The nearest metro station is Aghios Nikolaos on metro line 1 (green).
Bus schedules to Delphi are available here: (select itineraries and Delphi)
https://www.ktel-fokidas.gr/
The first bus leaves from Athens at 8:30 a.m. The journey takes approximately 3 hours depending on traffic.
In Delphi, the bus stop is located at the entrance to the village of Delphi, right next to the ancient site of Delphi.
Going to Delphi with a private driver costs around €400. By bus, it's €33 for the return trip.
I want to walk the ground of Plato’s Academy
Plato's Academy Archaeological Park is located here.
https://maps.app.goo.gl/adRUmEtkTzsG9Cjd7
I recommend taking a taxi. It's also possible to get there by public transportation, but it involves taking the metro, then the bus, then walking.
I am trying to fit in the National Archeological Museum
In a single day, you can go to Plato's Academy early in the morning and then the NAM. You must finish your visit to the NAM early enough to catch a taxi and leave for the airport in time to catch your 7:00 PM flight to Kavala. Allow about 2 hours to visit the NAM.
You must be at the airport 1 hour before the flight's departure time.
Allow between 40 minutes and 1.5 hours, depending on traffic, to get from the NAM to the airport by taxi.
To be on the safe side, I would leave the NAM no later than 4:00 PM.
The Athens City Pass is confusing
There's no point in buying passes, which will be useless and expensive. The passes offer combos of site and museum visits. You'll pay for all these visits, plus the commission of the third-party service selling the pass, even though you won't even see 50% of these places.
Be smart and don't get scammed by tempting expensives passes. Simply buy your tickets at the entrance to each site/museum you visit.