We rented a car which worked out great (in our 60s) and toured all over Italy including Sorrento and Amalfi. In your case, you might consider hiring a car service or shared shuttle (reserve in advance) from train station (or airport) in Naples. Others may have better suggestions. We did enjoy our stay in Sorrento. Amalfi Coast even in April was pretty busy but spectacular-driving there may have been the most "interesting" (not in the most positive sense) part of the trip.