Peloponnese, Island, Athens - Help with Itinerary

I freely admit we were okay with the drive to Nafplio from ATH after an overnight flight from the US east coast, but we would not have been up for a lot of driving around that day (and found on another trip that it is best to drive straight to accommodation on arrival day, not touring with jet lag, as it can come on quickly). Best to make sure both are drivers on the rental contract just in case.
The next two days could be spent in Nafplio, and you would not run out of things to do. I'd strongly consider keeping your trip to the Peloponnese rather than trying to fit in Northern Greece too.

On June 19th are you sure you want to stop at Ancient Nemea and / or Mycenae before going to Nafplio and after a long flight?
It might be more reasonable to combine these visits with the visit of Epidaurus on June 20th. Mycenae and Epidaurus can easily be visited in one day with a "beach / lunch" break in between. Especially in June when the sites close at 8pm.

Theatre of Epidaurus - tour or drive?

Why would you go with a tour when you have a car?

Your itinerary is very busy as usual with the first drafts of itineraries.
You will spend a lot of time on the roads. A good part of which is in a semi-mountainous environment where you will not drive more than 40mph with a rental car.

I don't see how it is possible to do a Delphi - Meteora tour in one day. You may have confused it with the itinerary of a UPS deliveryman :))

In my opinion you will not visit a region and its sites, you will consume them from the seat of your car (or from the tourist bus). And if you also want to visit an island + Athens it becomes rather unrealistic.

Jo-Lui is sensible and diplomatic -- These itineraries are not realistic time-wise, and may involve misinformation. Please re-think. You mention your son as a history buff, whiich I'm guessing means classical history, ,which Meteora is not. Even If he's interested in relligious history, of Greek church resistance during centuries of foreign occupation and repression, there are other more relevant sites. Meteora imho is more a scenic landmark, an ambitious driving/time investment in such a short trip. Olympia is not 2 hours from Sparta. Besides research on Youtube, have you explored guidebooks like Blue Guide, Rough Guide, Cadogan's etc. Example - Sparta shows almost no indication of its classical past, Thermopylae is marked only by a monument. Monemvasia is about medieval fortification, All-day tour to 3 sites named would be a drive-by blur.

My suggested option (use this map to follow - https://tinyurl.com/zekuft9)
June 19 - Arrive, drink espresso, get rental car (book for 2 drivers, to trade off)-- jump off big highway at Isthmus for photo-op at Corinth Canal, then continue to NAFPLIO, check in, stroll town, sunset dinner, early night
June 20- 21 - 22 -- in 3 full days, visit and appreciate Old Town, stunnng view from Palamidi (drive up back way, your son can climb the 999 steps!) Ancient NEMEA (a great "stand=in" for Olympia) MYCENAE, TIRYNS -- this fab website http://www.visitnafplio.com tells all - click every link!! Great swims at town beach (not Tolo) or hidden cove by ANcient ASINE. Enjoy Nafplio sunsets, best in all Greece
JUNE 23 - check out 9 am - drive EAst across PElops "thumb" - photo stop enroute at Bronze Age (!) bridge - https://en.wikipedia.org/wiki/Arkadiko_Bridge - visit Ancient EPidaurus (mainly the fab theatre). drive up Seacoast to Isthmus, get lunch then back on Big intercity highway. Turn LEFT At Elefsina, N to Thebes & Delphi. Arrive late in day (after tour mobs leave),check into hotel, visit museum (open til 8), sunset dinner, looking down mountain to sea. Aaah
JUNE 24 - enter ruins 8 am, 2-3 peaceful hours before bus throngs invade, then leave for Meteora (if you must, sigh) & spend June 25 there and drive back in the dark.
JUNE 26 - 27 - 28 - Athens
-- Alternative: Return to Athens JUNE 24 afternooon ... tour ATH 25- 26.

JUNE 27 - Early AM, Metro to PIRAEUS for wonoderful Day trip to nearby island of AEGINA; check this photo album for how to: http://www.flickr.com/photos/36264706@N03/sets/72157621604646139/detail/ Note: only take OPEN-DECK ferry (not hydrofoil) - u can check timetable & buy tix day before near hotel. Rent car or e-bikes to visit fab TEMPLE there, then enjoy beach swim.
JUNE 28 - Final day of Athens sight-seeing, late-day to airport & shuttle to AVRA

Thank you all!! I really value this groups experience and have deleted my itinerary as I don't want to spend the majority of time in a car, nor am I comfortable driving on mountainous roads. Meterora is off the list as well as some others. I appreciate the specifics that you provided Janet and will use the links and suggested itinerary as it looks great.