Where to rent a car in Tuscany

We picked up our car in Orvieto as we were headed to our Agriturismo in Siena. We were able to spend some time in Orvieto, which was a lovely town. We then made the easy drive to Siena. We returned our car at the airport in Florence. You dont go through any ZTL's to get there. You don't have to return a car in the same place you pick it up.

Take train from Rome to Orvieto (just over one hr).
Visit Orvieto for a few hours, it's worth it. Ask the rental car company (they are all near the station) if they can hold your luggage while you visit Orvieto's historical center.
In the PM, before the rental office closes, pick up your car and drive to your location north of Siena. Keep your car for your entire stay, you'll need it for an Agriturismo.
On the day of departure from Siena, drive to the Cinque Terre. You have no need for a rental car at the Cinque Terre, therefore I propose these options.

Option 1. Drive to the Cinque Terre (Monterosso? Riomaggiore?). Download luggage and passengers and tell them to go to the hotel and check in. You can accompany them if you want, just park your car in a lot for the time necessary to check in. After downloading luggage and passengers, drive your car back to La Spezia (near the Cinque Terre) and return your car there. Take care of the paperwork, and take a taxi from the rental car drop off (most are near the port, AVIS is near the station) to the La Spezia train station. Take one of the frequent trains to the Cinque Terre (10 to 20 min) to join the rest of your party who in the meantime will be enjoying life at the beach.

Option 2. Instead of driving to the Cinque Terre to drop off your party, go straight to the car rental drop of in La Spezia. Drop off your car and with the rest of the party (and the luggage) take a taxi to the station, then all of you take a train to your Cinque Terre town of your choice.

Either option works. I know my family would go for number 1 and let me do all the work (like downloading the luggage from the car, wheeling it to the hotel/apartment, driving back to Spezia, returning the car and travel back with the train) all by myself while they enjoy a drink at a bar in Monterosso. I'm basically my family's servant Sherpa.

We picked our car up in Florence and dropped in Rome near the Borghese. It was a little hectic, but no worse than driving in a major city. For us, it was cheaper than the smaller towns and we stopped in Orvieto to visit along the way. I would also suggest Civita di Bagnoreggio if you have the car by Orvieto -- it's only accessible by a ped bridge and seems untouched by time.

You could take the train all the way to Florence, and take a cab to a rental car office. Then, you can drive through the City of Florence to a four lane highway that takes you to Siena in 1 hour.

After a 70 minute ride from Rome Termini, the Orvieto Hertz office is 100 yards from the front door of the rail station. It's just an easy, non-hassle place to pick up the car. From Orvieto to Siena is just about 90 minutes by a controlled access highway. Or, you can take a scenic route around Lago di Bolsena, west of Orvieto.

Orvieto is a very popular hill town for tourists, and a very pleasant place to spend a night or two.

Why do you want to avoid picking up a car in Siena? That was my plan.

I believe there is a car rental beside the train station in siena which is a little out side the town. So you don't have to deal with inner city traffic. This was our plan before I realised we have to travel to florence first to reach siena. We will be traveling from naples. So we are looking for a new plan now.

We are planning the thing -Rome to Siena to Cinque Terre. We are considering picking up a car in Rome at the Tiburtina Station. Not sure of the benefit of driving to Orvieto to pick up a car.