It would help us to advise best, if you would share - are these 5 days y our total time in Greece? Or will they be followed or preceded by weeks, on various islands? If its your ONLY Greece time,my thoughts:
• Do NOT do the 3-island ferry tour... it's all about getting on/off the boat, not much time ashore at all.
• For 1-day island & ferry experience, I highly recommend AEGINA. Green line Metro (30 mins) to Pireaus -- or a taxi will run about 25E. Buy tickets at any seafront agency for a REGULAR ferry -- NOT hydrofoil. The latter are assigned-inside seats, NO deck, no view. On REGULAR ferry you sit on deck 50 minutes to enjoy seascape -- huge cargo ships and cruise liners, ferries, yachts, sleek motorboats, tiny sloops ... maybe even a dolphin!. Aegina harbor is charming... a ruin right next to dock for photo ops. But for 4, rent a car & go inland ... beautiful flowers, monastery and then TA-DA! best-preserved ancient temple of any island Temple of Aphaia on a high hill... 360° view of entire Saronic bay. Move on to a beach, a relaxed lunch & a swim, back to port to explore back-streets, then dinner & sunset ferry. http://www.flickr.com/photos/36264706@N03/sets/72157621604646139/detail/ is photo album of a June Day in Aegina ... and a photo & website of a lovely cafe on a nice beach, Marathona -- http://www.aeginagreece.com/aegina/pages/beaches/la_palma_marathonas_cafe_bar_restaurant.html
• TEMPLE of POSEIDON is a tour-bus target for sunset,... but if you went there in the AM, it's deserted, I hear, then you could go down the hill to the beach below. But it's not a whole-day thing.
- That list of 4 Peloponnese sites sounds like a "RUIN-A-THON" that would exhaust you and your teens would revert to whiny 10-yr-olds. Way too much for an 8am - 6pm rush IF these interest you, edit. My choice for you? OVERNIGHT ADVENTURE in ARGOLID! Arrange with your hotel to be away ONE night ... they are VERY used to this, because so many tourists do bus trips. OR, you could check out, and for final night, book a pension close to the Airport. I suggest renting car at 8 AM, day one, returning by 5 pm day 2. (at airport?) and in the meantime having GREAT Discoveries. You can drive on Greece's MOST modern highway across peninsula (roads are level in a valley, no sick-making turns) stop at a GREAT "Games" site, explore nafplio in afternoon & sunset, In AM, off to Epidaurus before Noon, then a Corinth canal stop, back to Athens. . Here's a great Map http://euro-map.com/karty-grecii/peloponnes/podrobnaya-turisticheskaya-karta-peloponnesa.jpg -- click & it gets huge,
• ATHENS -- take BIG ROAD over Canal, 15 miles on, exit to to ANCIENT NEMEA, "runner-up Sacred Games Site" Ruins, temple, fab stadium with Athlete's Tunnel, and actual ancient starting blocks for runners! NO tour busses! Enjoy in 45 minutes. This is in heart of BEST wine district In nearby NEMEA village on Main St, there's a bottling place to watch bottles being capped & sample Nemean Red. Then on to NAFPLIO
• NAFPLIO -- This noncommercial website explains all delights ... http://www.visitnafplio.com/ Click ALL links! These pix show some glorious views http://www.flickr.com/photos/stanbr54/sets/72157632094108982/ Cllimb Acronafplia out to the POINT ... do the fab walk around point @sea level, do Greece's BEST sunset on the wonderful seafront promenade. Next AM you can drive up BACK way to top of Palamidi ... for the best views ever! Kids will love the "castle/fortress" ambience.
• RETURN ROUTE - At EPIDAURUS, theatre is main feature, u can skip ruins. To see Canal right, exit at "Isthmus" and ask way to Old Bridge a few blocks away & walk out ... So deep! so Skinny!
If this is of interest, I can recommend accommodations near airport, and in Nafplio.