I would suggest dropping the word "resort" ... that suggests an enclosed "bubble" atmosphere, which could be on a beach anywhere in the world that offers spas, massage and chitchat with a privileged circle. Instead, look for a place that is family-run, has amenities but not enclosure, doesn't attract the pampered-people and offers both relaxation and nearby interests.
My nomination for such a hidden eden -- Hotel Zoe -- in Gialova, about 8 miles north of Pylos, S.W. Coast of Peloponnese.
http://www.zoeresort.com
Someone 2 years ago talked them into renaming their website, but thank God, they are not a Resort -- it's a family-run hotel, one one of the most beautiful, unspoiled beaches in all of Greece. It's a 3rd generation enterprise (founded by Grand-dad, now managed by Grown-up college-educated, English-fluent Zoe, for whom it was named, and her handsome brother & the parents)... there are 2 buildings, the inland one(with family apts) facing a large pool the other directly on the beach looking thru a grove of palms to the water. Choose this one, with a sea-view shaded by a roll-up canopy. You breakfast under the trees (and dine too if you wish, lit by lanterns). Most guests are lovely, well-mannered Brits & Scandinavians. The town of Gialova is a few hundred meters off the north-south road... it's only about 4 blocks long, with a number of nice tavernas, a few shops and I think 2 other small hotels. The beach runs north about 5 miles to the Nature Habitat, and the gorgeous Bay of Navarino ... Castles! Wildlife! (A "luxe" hotel is up at that end, so how long this place will remain serene, lord knows). The Zoe owners are active proponents of environmental preservation and protection.
I first discovered this in a small paragraph in the CADOGAN GUIDE to PELOPONNESE & ATHENS (This is HIGHLY recommended; literate and insightful far beyond other guides). I came there from Olympia in 2009; took 2 local busses, finally ran out of busses, and cabbed the last 10 miles! In 2013, after an exhausting trip showing 4 energetic "newbies" my favorite Greek "highlights" I took a slow bus alone, all across the Peninsula, and plopped down for 4 blissful days of recuperation.
There is a small town pier next to Zoe, empty all day (it offers the absolute best view of sunset). Around 5 pm, cars pull up and Greek daddies pile out with their children to play in the water awhile before going off to dinner. Once in awhile, an elegant small yacht will anchor nearby. That's all. Enjoy -- and if Zoe asks, say thatJanet from Philadelphia sent you.