Your reference to Fontwell caught my eye. My favourite bit of Sussex road is between Fontwell and Storrington... fantastic views, curves you can see across, nice hills, sweeping bends, tight corners that can be taken quickly if you get the line right - it's got everything whichever direction you're going in.
This. I love this drive (which I do throughout the summer, as I live in Hampshire, but play cricket at Parham). Over Houghton Hill and the viewpoint, down though Houghton and Amberley, then left on Rackham Road, through the woods to the back gate of the Parham Estate.
That to me IS Sussex.
Home.
#sigh