My husband and I are planning a trip to the Greek islands in June. We plan to meet up with another couple in Athens and then stay at approx 3 islands over a period of 8 nights, 9 days. We thought of staying on Mykonos and Santorini definately. The question is which other island - Naxos or Paros or even Ios? Or do day trips only? - I see that Delos and Syros are recommended. My only concern is the cost - I understand that Santorini and Mykonos are very expensive, so staying on another cheaper island for a couple of nights might be the best option. Any advice would be greatly appreciated.
Also do we need to book accomodation between 7 and 15 June?