rent car italy, pick up florence, return rome

is there a better place to drop off hertz car closer to downtown Rome?

When you researched renting the car from Hertz their customer service does not say all the places where you can drop it off in central Rome?

I don't know how you came up with 1800 euro for train fares for the trips you are taking. Unless you were planning to buy all the 40+ seats in a train car each time.
Florence to Naples (Napoli) is 75 euro (full base fare) p.p. Napoli to Rome is 45 euro pp (full base fare). And those would be the only expensive tickets aboard high speed trains. All other segments you are considering are aboard Regional commuter trains, which cost peanuts.
Nevertheless renting a car to visit Tuscany is a good idea, since visiting small towns is more efficient with a car than with trains and buses. Pisa however is much faster to be visited from Florence on a half day trip. 48 min by train (one way) for 6 euro per person. The car can't compete, especially once you include the time to find parking and pay for parking. If you are in Florence for any extended period, I'd visit it from Florence by train (2 hours in Pisa and you are done).
There are many Hertz locations in Rome. If you come from the south, Ciampino is good. But of course there are many others closer to the center. Just go to Google Maps and in the search box enter: HERTZ AUTONOLEGGIO. A bunch of locations will pop up. Where you want to drop off, will also depend on where you are staying in Rome.
The Tiburtina or the Termini station are good and close, provided you don't get scared driving into big cities.

My overall opinion of your trip is that you are trying to squeeze too many places, too far apart, into few days. 2 nights only in Sorrento? Really?

Tuscany is quite large. Have you figured out what sights you want to see? Two years ago, after having been there several times before, we spent 10 days in Tuscany. We still haven't seen everything worth seeing.
Your plan for Sorrento doesn't give you much time there. Driving will take a big chunk of time from your first day, and you plan to go to Pompeii on the second.
I suggest you cut out Sorrento. Have 2 bases in Tuscany, one in the north, the other in the south. Or use Orvieto (not in Tuscany) as your southern base. Get a guidebook, Rick's or other. Find out what there is to see. Having a car is very useful in Tuscany. By the way, are you not including Florence in your itinerary?

Hello All
I wanted to reply to my own posting, with my findings, reasons and comments.
I was HOPING someone who has returned a rental car in Rome would give me the "use this hertz office not that one because..." or the do not do this to avoid fines or expensive parking... and so on but that did not happen.

1. IF YOU WANT TO RETURN HERTZ RENTAL IN ROME COMING FROM SOUTH:
Use Hertz office at Via Tuscolana, 1530/1546, 00174 Rome (note they are closed sundays). This location is outside the ZTL zone and short walk from Cinecitta Metro train stop. So you can ditch the car here grab bags and family get on metro train and continue with your vacation. If you arrive late at night or on Sunday return car at Airport.
2. WHY RENT A CAR?
First I agree if you only want to see 2 or 3 cities... use the train. And driving in Italy is NOT relaxing.

But if you are planning on visiting the Tuscany, Assisi and other little towns in that area AND have family of 4 the car starts to be more economical.
3. DRIVING PERMIT IS CHEAP... GET IT JUST IN CASE
I got my international driving permit at AAA office for only 20 USD.