Just read MarciaB's post (6 Sleeps on 6/10) and find that her itinerary is much like ours in late Sept. and early Oct. We (2 couples) arrive and spend a few days in Rome, move on to Praiano for a week and then head for Umbria for a few days. We plan to use public transportation from Rome to Praiano. Following our stay in Praiano, we're considering taking public transportation from the Amalfi area back to Rome, renting a car in Rome and then continuing to our next stop, Spoleto. Any comments on the wisdom of this plan vs. renting the car in Praiano and driving entire way to Spoleto? We will ultimately return the car in Rome prior to our return to the US. Any comments or alternate plan suggestions would be appreciated. Thanks in advance.
B&PR

Here is another plan: Take the train to Spoleto and rent the car there. You won't have to deal with driving in Rome. If you are staying in Spoleto you could save a day's rent and pick the car up the next day.
Brad

We are renting our car at the Naples airport after our Positano stay. We had thought to get it in Sorrento, but found we had more options for cars by going to Naples.

However, since we decided to use private transportation (car service) from Positano back to Naples, so I'm not sure if this is helpful to you. On our way down from Rome, we are taking the train to Naples, then using the same service to transport us to Sorrento. We will probably take the bus for the Sorrento to Positano leg. Admittedly, this transportation thing is the splurge of our trip.