Thank you for the detailed and interesting introduction. Welcome to the site.
Just to add to what Scotty said, as I also drove on that trip through Greece, I agree that most of the roads are in an awful state and are of a poor standard. However... the one thing I will add in favour is that there were a fair amount of wide single carriageways, and I noticed that they actually knew how to drive there by pulling right over and leaving you plenty of space to get past, unlike in Britain where most slow traffic hogs the road up to the white line and stops you from getting past.