5 full days in Greece

Does five days mean six nights in GR? The reason I ask is because you lose a day when traveling from one place to another.
The only nonstop flight I see in late Oct is from IST to ATH. You could rent a car at ATH airport and drive to Nafplio.

Yeah 6 nights, 5 days.

I felt the Archaeological Museum in Athens is not to be missed, and 6 days is quite a short time. Nafplio is a good suggestion because it's a lovely town and not far from Atherns. We were very glad to have seen Mycenae on the way. Santorini I could have done without, but Delos was another wonderful site. Crete is lovely, both Rethymno and Chania, but Heraklion is quite awful, though the archaeological museum was fantastic (but not Knossos).

Drive to Nafplio, return for a night or two in Athens.

Agree with valedelphia ... because NAFPLIO is SO lovely, not a city but town at tip of peninsula, surrounded by sea, feels like an island. Italianate architecture, considered THE most beautiful Old Town in Greece. & nearby, top historic ancient sites. Also fabulous short walks. Sit in harbour promenade cafe for loveliest sunsets in all Greece (& i've watched sunsets in dozens of isles). Another Naxophile, photo ace "Stanbr" shows highlights of city & area: http://www.flickr.com/photos/stanbr54/sets/72157632094108982/ For the ultimate guide in what to do/see/eat, check this superb noncommercial website - http://www.visitnafplio.com/

It's also a relaxing 2.5 hour drive from/back to Airport.. so you can have your final 2 days in Athens. Use another map in car, but browse this - https://tinyurl.com/zekuft9 -- because shows entire route from Airport, plus terrain, differences among roads, also key sites (click & it gets Huge, you navigate w side-slides). Modern divided intercity highway skirts Athens, stress-free nonstop into Peloponnese, then easy final 30 minutes on no-traffi local road. through rolling countryside, citrus orchards, olive groves. (PS: if you don't want to drive, you can taxi to Kifissou KTEL bus terminal for intercity bus, modern, reserved-seat, prompt express runs on same route, runs every 2-3 hours, about €15). In Oct,. you have a chance at bookinig the Best-loicated lodgings - Hotel Agammemnon, right on sea front, or else a v nice boutique pensoion nearby Omorfo Poli.

IF you DO decide to rent car, here are some highlights u can stop at:
-- Corinth Canal (exit @ "isthmus" for 20 mins to go on Old Bridge for fab photos)
-- Ancient Nemea (10 miles past canal, just 5 mi off highway... a stunning "Olympia runner-up" games site! NO crowds, splendid stadium, authentic, now used for "revived Games".
-- just 10 mins outside Nafplio, ANCIENT TIRYNS - a huuuge Fortress, (quick easy visit vs. Mycenae bus crowds)
-- AM on return-day, take alternate route: drive across "thumb" of land (see map) stop at Ancient Epidaurus for an hour .. not for its ruins, just for its awesome world-renowned ancient Theatre seating 15,000 & perfect acoustics. Then drive up seacoast to Canal tor rejoin big highway back to airport. Then u can taxi (flat rate €42 to Central Athens) for 2-3 final days.

wow Janet, this is such great information. I am going to follow it!

I am just paying it forward... on my first trip to Greece (an age ago, May '99), I visited a sequence of islands, last one Mykonos, back before it was Crazzzy, staying w friend of a friend, Americaan artist married to Greek. I said, I guess I'll go back and spend 3 days in Athens. And she said, no, you'll store your big heavy bag at the hotel, go to the KTEL terminal, and take a bus to Nafplio for 3 days. And I said, but what is Nafplio? never heard of it. And she just said, you'll thank me. Nafplio was a whole new world, a visual, historical, gastronomic treasure. I stayed in a tiny room at top o' town, swam in the amazing stony "town beach," thrilled to the museum, sighed at the sunset..., and said I must must come back. I think I've returned at least 6-7 times, have brought along travel companions to surprise & delight. And every time I think, Thank you Angela.. I'll share this.

Amazing! Thank you Angela!