We visited Santorini in November, 2011. I swear we were the only family on the island. The streets were deserted. We hired a car and did pretty much the same thing as you and Chris did. Akrotiri was closed but we drove up to Ancient Thira. It was so scary I decided I'd walk down by myself. The search started when the rest of the group couldn't find me! There weren't many people around to ask. I wanted to swim in the thermal waters of the caldera, but we couldn't convince anyone to take us out. I'm going to see if i can find where I wrote about it.