Hi there....as part of our upcoming honeymoon, my wife and I will be driving from the airport --> Nafplio --> Olympia --> Delphi --> Kalambaka, and back to the airport. Any advice/recommendations for car rental from the Athens airport? Is GPS through the company a must? What about the insurance they sell? We'll be returning the vehicle back to the airport so we won't be driving it in Athens. And we'll need it for 7 days. I've done some looking online at various companies, but there are a bunch of options, so I'm just hoping to get some guidance. Appreciate any insight/advice!