I stayed on the island of Santorini for 4 nights, at the Santorini camping site.
The highlight of my stay on the island of Santorini was undoubtedly Ammoudhi Bay. It is at the base of the city of Oia. I visited it twice, once on the day that I rented an ATV, and again when I walked from Fira to Oia (which took 3.5 hours at a fairly slow pace.) I spent about 3 hours at one of the restaurants once again trying to figure out how to paint with water colors. On the day I rented the ATV, I spotted some hip scarecrows on their own vehicles.
I loved the island of Paros and didn't get to spend enough time on. I spent 2 nights there, staying at Rooms Mike, which I highly recommend. Mike is super friendly, and made me feel very welcome. Paros is all about the beaches and relaxing. I spent 4 hours or so just chillin in one of the cafes, watching people walk by. But my favorite excursion was to the Marathi ancient marble quarries which are caves in the side of the mountain. You have to bring your own flashlight, and since I was the only person there, I stayed in the main part of the tunnels. They were amazing.