[MENTION=740026]nk15[/MENTION]: 100% correct! [MENTION=10117243]frappant[/MENTION]: Well, you had mentioned Corfu in the OP. I think that Rhodes, Crete and Santorini may be enough, Crete is big enough and worth visiting from the extreme east (e.g. Zakros) to the extreme west (e.f. Falasarna and/or Gramvoussa. I'd leave the Ionian islands (which I personally love) for the next time...

Fly ATH-RHO, then RHO to either JSH or HER, get a rental car anf go tp Santorini with one of the superfast cats. From antorini to Piraeus you could take a conventional ferry and "see" a few islands (their ports, et least) on the way.