I'm more than a little jealous.... I'm sure they'll all have a blast. It's hard to be in a bad mood in a place like that
Another thing that occurred to me that I
would have fun doing, and would have loved to do as a kid, is geocaching. Apparently it's fairly active in that part of the world as well. I just googled "geocaching in the cyclades" and got a bunch of hits. Just find some caches that are at your daily destinations or along your passages; your 8yo can probably even help with the navigation. Having something mysterious to look forward to can make the time fly by a lot faster.