Which days need a car
Onna, the aquarium, Kouri, the sea road, Mabuni, Zanpa. Kerama does not need a car on the island.
Pickup and return
Do not pick up the car for a walking Naha day — parking on Kokusai-dori is slow and costly. The Okinawa Expressway runs from Naha toward Nago; an aquarium day on it is still a full day. Keep left. On a night you drink, leave the car at the hotel. The return day needs airport time — not Cape Hedo or Kerama.