Well, I can only speak for Santorini and Athens...so I don't know about the other 200 or so inhabited islands. But apparently you can, since you say "aside from santorini, everything..."
How long did it take to visit over 200 islands? Did you go to the over 1000 other uninhabited islands also? I assume you've also been around the over 40,000 square miles of mainland too?
I enjoyed Santorini. Wasn't too bad as far as being expensive. The single most expensive part was the airfare.