Greece Trip Report: Sept. 2019

Forum posts helped me plan my recent trip to Greece so I offer my experience. If not useful, please ignore.
Itinerary: 2 nights Athens, 3 nights Nafplio, 2 nights each Santorini, Naxos, Mykonos.
Credit Cards: No trouble using my American Visa card. It has a chip, no pin.
Water: Despite what many say, I had lower GI distress w/in 2 days and switched to bottled water, no fresh fruits/veggies, no ice. My symptoms cleared. Locals on the islands said don't drink the water.
Language: Everyone speaks English.
Toilets: Guidebooks say put toilet paper in the nearby trash can, not in toilet. I saw only 1 sign w/this but followed it.
Buses/boats: They may be early. Be ready or you miss them. Not all buses are well marked so ask the driver. Your ferry reservation is not a ticket unless you see a barcode. Get a printed ticket at the port. Be ready when your boat approaches. The well marked boats stay at the dock only a few minutes to unload/load passengers. Be efficient with yourself, luggage, ticket.
Shoes: Day hikers are a must for slippery stones everywhere.
Safety: I am a female solo traveler and never was afraid. Just keep obvious control of your purse/wallet.
Athens: Express bus (X95) and its ticket window was right outside Exit 5. It makes stops, but ask the driver to announce the Syntagma Square stop (about an hour). 6 euros each way. The return bus to the airport leaves from this same spot regularly. I walked a short distance to the Electra Palace Hotel in the centrally located Plaka. I registered online with the hotel rewards program and used my free drink at the pool with a view of the Acropolis. The Acropolis Museum and the National Archaeological Museum are superb. Do not use a taxi in Athens near any tourist area - I was badly ripped off (wrong location, high fee).
Nafplio: Driving to the Peloponnese from Athens airport was easy. Look at a map before you start and follow well signed good roads. Pay 4 tolls with euros or credit card. The exit for Nafplio was well marked and I took that same exit to see Ancient Nemea. Nemea is north and Nafplio south. Old town Nafplio is charming. I stayed by the water in the Grand Bretagne but it was very noisy very late. Day trips to Epidavros and Mycenae were easy and must see. Nearby beaches are in Tolon and Karathona. The view from Palamidi fortress is a must see, I drove. I recommend Aiolos restaurant and Antica Gelateria di Roma.
Santorini: Flying to Santorini via Aegean Air is 45 min. I rented a car at the airport for 24 hours and returned it in Fira, then used the bus. Be prepared for driving lots of uphills & downhills with tourist buses on many hairpin curves. I stayed in lovely Oia in a studio cave dwelling at Chelidonia. Park at the public parking garage and call your hotel to meet you. The crowds are awful at sunset at the tip of town (castle ruins) but otherwise fine. I recommend eating at Candouni in their charming courtyard or Roka, and Solo Gelato is a must. I drove to Akrotiri archaeological site followed by the Pre-Historic Museum in Fira. Eat souvlaki at Lucky's in Fira near the bus station.
Naxos: The ferry leaves Santorini from the port in Athinios which is a crazy scene. Leave extra time to get there and be sure to get in the right queue for your boat. Naxos is a 1 hr, 10 min. ferry and more authentic (no big airport, cruise ships). I enjoyed Iliada Suites in the Grotto area with a balcony overlooking the Portara, the place for sunsets. I recommend eating at To Elliniko and Nostimon Hellas, away from the port. I took the public bus from the port to inland villages and hiked above the town of Chaliki. Read hiking maps online; paths not well marked. You see small Byzantine churches.
Mykonos: The ferry from Naxos is 35 min. I loved Ostraco Suites, quiet with a lovely view, pool, 10 min walk down to town, where you will get lost. The bus to inland Ano Mera is fun and has a great hike. Have fun!