All the "vets" agree (including me.... Nafplio & surroundings is your very best bet, because it truly will have something for everyone... the drive there & back has great stops along the way... on a peninsula it's surrounded by water, so gets the island feel... ... and you have ancient sites galore to choose from. Stanbr's pix are a great start, and here's my fave online map to show your route & highlights- https://tinyurl.com/zekuft9 -- (click & it gets huuuge & you navigate around with side-slides).
The easiest thing probably is car rental (& for 4, no more than 4 bus fares & much more useful onsite); jump in a car-service (about €42 flat-fee to airport, 45 mins) pop into car & drive on Modern divided highway much of the way... avoids city entirely, need not even tap brakes until Corinth. Here are a few Highlights going, returning and when around Nafplio --
• CORINTH CANAL -- Either outbound or inbound, pop off highway at Isthmus for 15-20 minutes, just to see and photograph this really skinnny really deeep wonder.
• ANCIENT NEMEA -- outbound, 15 miles or so after canal, just off highway to your right -- a short stop for this "Sacred Games" site (runner-up to Olympia) with super stadium... today Greeks have a "revived Games" every 4 yrs; thrilling & u can enjoy in an hour.
• NAFPLIO itself - Considered most beautiful Old Town in All of GReece -- if u r lucky u can book Hotel Agamemnon, BEST locale right on seafront, if not, Omorfo Poli nearby is v charming. Parking is free right at waterside. Wandering town deserves at least half a day, and its seafront cafe promenade is front row seat for sunsets more glorious than Santorini. The "town beach" Arvanita is a lot of fun, on other side of the Massive town heights... or u could drive 15 mins to TOLO. As for mighty Palamidi, instead of 999 steps up, drive around the back;.. it's a MUST, for the view! if any in group insist, they can walk the steps Down.
• TIRYNS -- many people devote 5-6 hours to Mycenae, but if you want a mighty Bronze Age Fortress with less time/effort, TIRYNS is just 15 minutes outside Nafplio... no museum, but same Huge Boulder Structure, very impressive. You'll be only ones there!
• EPIDAURUS -- you don't have to go there, then backtrack to your Nafplio hotel... Take look at Map -- you can visitt on your drive BACK to Athens area. After checkout ono final day, drive EAST across "thumb" of Peloponnese to This Famous Site. It museum is meh, & acres of ruins are confusing but Theater is THE star,... and it's Stunning. On leaving keep driving East to seaside.. you can stop for lunch (maybe a swim?) going up shore road to ISTHMUS (and canal) where you join the big highway. Only precaution -- be sure to turn LEFT at Elefsina (see map) to that Bypass to Airport, to avoid horrendous truck-route into Central Athens.
