THE PLAN BEFORE THE KEYS
Follow the coast. Then take the road inland.
Naxos is the largest island in the Cyclades, and its inland villages give a rental car a clear purpose beyond the beach. Halki, Filoti and Apeiranthos offer a different day from the western coast around Agios Prokopios, Agia Anna and Plaka. Choose your base first, then group your outings rather than trying to cross the island for every meal and swim.
A compact car can suit a couple with light luggage. Families should compare actual boot space and child-seat arrangements; the seat count alone tells you little about a loaded airport transfer. An SUV is a comfort preference rather than blanket permission to use unpaved routes. Ask which roads your operator permits and build a realistic plan around your driving confidence.