We will have a car for a week in the Tuscany hill towns, and then plan to drive south toward the Sorrento area for 3 or 4 days. Would you recommend keeping the car in Sorrento/Naples/Positano area or turning it in and using other means of transportation?
If you want to really explore the penninsula - keep the car. But if you just want to stay in the main tourist areas - get rid of it. We had a car for a week there the end of July and had a fabulous time. We even drove the Amalfi coast from Sorrento to Paestum - with no traffic hassles at all. But we were lucky. We did not attempt to park in Positano nor Amalfi Town but took the ferry there on another day.
With the car we were able to explore Massa Lubrense, Nerano, and Termini.