Best driving route Rome to Sorrento? Any interesting stops on the way?

Linda, I'm just curious why you're renting a car if you don't intend to use it other than driving from Rome? It seems like a waste of rental/parking fees to let it sit for 4 days...unless you're just renting it for a one-day the drive between Rome and Sorrento? I'm not sure I'd rent one for that. You could do Pompeii or Herculaneum by train enroute to Sorrento, and both have luggage storage...which I'd personally prefer to leaving anything in an unattended car.

Editing to add: as noted below, make sure you're aware of Sorrento ZTL restrictions.

We will be taking trains and buses to the Amalfi Coast, Capri and
Pompeii/Herculaneum/Naples

You'll obviously need to take a ferry to/from Capri, and many of the island's businesses will be shut up for winter although you could still do some hiking around.

http://www.capri.net/en/ferry-schedule?from=sorrento&to=capri

Where are you going after Sorrento?

Make sure absolutely no luggage is visible when parked.
Research in advance and avoid any ZTL areas
Get an International Drivers permit at a AAA office

I would stop at either Pompeii or Herculaneum or stop to hike Mt. Vesuvius which are all near to each other and much closer to Sorrento than to Rome. By making a stop where you will want to stay multiple hours I would not want to add another stop and would want to go the quickest way possible otherwise (highway) ; maybe a stop for coffee and bite to eat at an autogrill. Figure if you drive all highway you probably have a 3.5 - 4 hour drive ; add a 4 hour stop at Pompeii and that is already a full day that in December will be all of your daylight.

A car is kind of a waste for the trip you are taking in my opinion but that is your choice.

I just realized you are already planning on stopping via train on another day to Pompeii/Herculaneum
I would advise you change either that plan or your in route plan.

Given you are spending 4 nights in Sorrento yet may only be allocating 1 day for seeing the Amalfi Coast (the main reason why people go there) I would not waste my time looking for out of the way stops and get to Sorrento as soon as possible from Rome
OR
Hit Pompeii and Herculaneum on the way down to free up a day while you are in Sorrento to spend more time along the Amalfi Coast. Keep in mind driving and seeing both those places will be a long, tiring day!

Thank you all for your responses. Kathy, the car comes with our travel package -- I won't get a discount if I drop it (though I have considered that). I don't mind driving to and from Sorrento -- mostly I don't want to deal with lugging baggage on a train and worrying about storing it.

MReynolds, I think driving and doing Pompeii etc. is going to be too much for me -- especially since we want to spend a lot of time there. I also thought we would train up to Naples after Pompeii just to see it and eat there. I will take your advice to get down to Sorrento asap and take advantage of being down there, I just know I'll need a brief break in the drive -- so maybe it will be the Autogrill after all....

Since we'll only have one full day to explore the Amalfi coast (given that we are doing Pompeii on one day and Capri on another), I'm wondering if I should scrap our included "Limoncello Factory Tour" in Sorrento and instead spend that time busing to Amalfi and Positano. I have seen the process of Limoncello being made and don't care that much about it, and I figure we can see enough of Sorrento in the evenings after our day trips.

We are driving to Rome for 1 1/2 days after Sorrento. Not enough time, I know, but all the time we can afford right now. We WILL return. :-)

Thank you again - Linda

Since you have a rental car part of the package I'd use it to drive to the Amalfi Coast, to Pompeii, and anywhere else but the island of Capri and Naples (driving in congested chaotic Naples is never a good idea). Traffic on the Amalfi coast should be minimal in December.

Thank you, Roberta. I am concerned about parking in Positano, etc., and also I can't drive at night at all (or when I'm tired. Or when I'm drinking). But I may drive the Amalfi coast as it will allow us to explore. Do you have any advice on parking?

-Linda

Yeah use the car to drive the Amalfi Coast road
Parking in December shouldn't be an issue. The SITA bus won't be crowded either I imagine so could take the bus if you prefer or are worried about drinking but I personally would drive if I already had a car and was going in Dec.

Skip the Lemoncello tour, you want to make certain you see Positano, Amalfi and beautiful Ravello.
You will find small Lemoncello shops that show on a small scale how they make the stuff all throughout the area so don't think you will be missing anything great.

Ravello is a small town that is above Amalfi, has a much different view of the sea, arguably better since it sits so high up. Couple of amazing gardens/villas up there which you have to pay to visit but have phenomenal views. Also some great restaurants in that little village.
Amalfi the duomo there is the main draw and is definitely worth seeing along with the surrounding grounds.
Positano you will need a few hours to explore the different back roads and alleyways which are actually roads. Many steps to climb here but a very different and picture perfect tiny town.
Going all that way and not seeing them would be a real shame ; will be a long day to see all 3 but doable.
Normally I would not want a car for any of these towns since there would be no parking most times but in December should be fine. All 3 are linked easily via the cheap SITA bus as well if you decide not to drive that day.

All 3 of your days will be VERY full so definitely reach Sorrento from Rome as direct as possible.

In December you should be able to find street parking (blue stripes don't mean handicapped parking in Italy, but rather 'pay/metered parking), white stripes generally mean free parking (but keep on eye on signs, in case it's restricted to residents).
In Positano there are also parking pay lots. The parking fee is generally around 2 euro per hour.