Four days in Okinawa; love snorkeling and island life. Help.

Hi there – I went to Okinawa years ago and can't remember much save for the fact that we visited Iriomote and Taketomi. Now returning with family. I have four full days. We fly down from Fukuoka to wherever we land. Have to return from Naha. Should we go to Ishigaki, Iriomote, Taketomi, Naha? Help. I am overwhelmed. We love snorkeling, nature, a little shopping.