score:4
(Anecdotal) I would never drive the amalfi coast.
We took the bus between Sorrento and Amalfi and it was just mind boggling crazy;
I suggest parking in Salerno and take a bus to your destination along the coast; after that, you can safely drive inland to Naples.
Public bus timetable : http://www.sitabus.it/en/salerno-to-amalfi-coast-bus-timetable/
Video of the Amalfi coast line road.