We used a web site, greecetravel.com, to find a villa to rent. We chose this site after doing a search on "villa rentals +Greece". There were several options, but this one is run by a woman who was very prompt in returning emails, and generally very helpful. We didn't have any idea where we wanted to stay, and she made a few good suggestions. We ended up on the south side of the Peloponnese Island in a resort town called Stoupa. It is considered a resort town, but it wasn't too "touristy". However, everyone did speak English, which was quite helpful, since we don't know Greek. Our house was about 1 kilometer from the sea, and backed up to the mountains. There were 3 beaches in the village, about 2 kilometers away.
We spent our week (Saturday to Saturday rental for around 650 Euros) exploring the island. The roads weren't great, so it took a while to get around, but it was beautiful. The countryside was rugged and wild looking, and the people looked as if they had lived and worked the same way for hundreds of years, with few modern improvements. We saw men and women herding their sheep and cows down the road, a man selling live chickens from the back of his ancient truck, and several of the grandmothers from "My Big Fat Greek Wedding". We saw very few vehicles newer than the late 80's, and learned where old busses and scooters go to retire. In fact, Mark thought he saw the one he rode in Jr. high! We boated on an underground river believed to flow all the way to Sparta, toured Olympia (the original) and Mystra, an important Byzantine city. We hung out on the beach a few afternoons, and paddle-boated in the Adriatic Sea. We ate some amazingly tasty spit-roasted hog and really fresh fish, but mostly we ate at home. We hiked up a steep hill, then climbed up a cliff to a ruined castle, and walked around the ruins of an old Venetian city. In a nutshell, we had a great time. We didn't make it to Athens, since it would have been a 5 hour drive each way, but we kept busy where we were. Gas was at least 25% less expensive, and that was for full service!
Our return trip was much the same in reverse. We drove straight home from Ancona, an 8 hour drive.