Considering your interests (great food, hiking, beaches, nightlife unimportant) then Naxos should definitely be your other island. (And Naxos has many daily ferry connections with both Santorini and Athens.) Also, Athens needs at least one full day to explore so you should drop any thoughts about Delphi or Nafplio. Also, I would look into flights from Athens to Santorini on your night of arrival. If you could get to Santorini that night (and move your day in Athens to the end of your trip) you’d almost gain an entire day and could spend two nights on Naxos.
The island’s next hotspot may be The Shore Club, the only development on Providenciales’ Long Bay Beach with 106 ocean view suites and six luxury villas on a nine-acre stretch. On popular, pristine Grace Bay Beach, Grace Bay Club’s tropical-chic redesign led by interior designer Thom Filicia includes redesigned lobby and guest rooms, the new Infiniti Restaurant and Raw Bar and The Residences, a trio of freestanding, beachfront villas. To get off the radar, the eco-conscious Sailrock Resort debuts this year on untouched South Caicos Island — secluded beaches are the buzz.
My fiancee and I are heading to Greece in July. We’ve been to Naxos, Paros, Mykonos, and Santorini. This time we plan on being there July 1 to 23. We’re definitely including Milos, and one of Paros or Naxos. Any recommendations for other islands? Any particular ferry routes we should consider? Some “less touristy” islands are a must (for at least one island). We can be lively or very chilled. Thanks and best wishes!