All this nashing of teeth about driving in the area. If you are a good driver, you'll do fine.
On one trip to the Amalfi Coast, we got to Sorrento by (ultimately commuter) train, then kept a car for 4 days and drove to Pompeii, over to the Positano/Amalfi side twice, once all the way up the coast to Ravello.
Next trip, drove from Tuscany to Positano, taking us within a couple of miles of the Naples Airport. Then kept the car and drove all over the peninsula again.
Sure, the drive from just west of Positano up the Amalfi coast can be a bit nerve wracking at times (think having to back up the road to let busses or trucks around the hairpin turn), but driving from Naples to the peninsula was a breeze. Plus driving up the coast is a ton of fun at the end of the day.