Logistics of stay in Tuscany and Italy itinerary

We rented a Hertz car in Florence and returned it in Orvieto. Then we took a 70 minute local train ride into Rome Termini.

The Orvieto Hertz office is across the street from the train station, and it's a popular pickup/drop off office.

It's really nice to see Tuscany with a car as the trains don't go to all the hilltowns that are so popular. The Tuscan roads are well paved and well marked, but just a little crooked. And there are a lot of controlled access highways going toward Rome.

We did same thing. Rented from the Florence Sud Hertz office and returned the car in Orvieto. Be aware the Orvieto office closes for a few hours for lunch every day. If I recall, they reopen at 3pm, but you can check.

Ciao Jores,
You have a very aggressive itinerary for a 16 day trip. Keep in mind that each time you change cities you are essentially losing a day to travel. So, if you just want to "dip your toes in the water" of each of your selected cities fine; but if you want to "take a swim" you need to decrease the number of cities you visit. If you want to your friends to see anything of note you probably need to spend at least 3 nights in each place so that you have 2 days of sightseeing.
Concerning Tuscany, I would recommend that you take a bus (or train) from Florence to Siena and rent a car at the Siena train station or conversely you can take the tram from the Florence train station to the airport and rent a car there. (From the airport it is fairly easy to reach the major highway heading south.) I would not recommend driving inside the city of Florence!
From Siena you can drive south on the S2 and enjoy the beautiful countryside. Returning the car in Orvieto and continuing on to Rome via train is a good choice.
Your itinerary might look like this:
Day 1 - Arrive Venice
Day 2-3 - Venice
Day 4 - Travel to either Bologna or Cinque Terre
Day 5-6 - Bologna or Cinque Terre
Day 7 - Travel to Florence
Day 8-9 - Florence
Day 10 - Travel in Tuscany -perhaps spend the night in Montepulciano
Day 11 - Travel to Orvieto and spend one night. Return the car.
Day 12 - Train to Rome
Day 13-15 - Rome
Day 16 - Return home exhausted but very happy to have visited in Italy

I hope you have a great trip!

We rent cars in Florence on Borgo Ognisanti which is near the Autostrada to get out of town.

Thank you all for the advice. I will definitely do the car rental near Florence and return in Orvieto as you all recommend. Charylm, I guess I was thinking Bologna could possibly be a day trip from Florence? Or possibly stop for a few hours in Bologna on the way from Vienna to Florence or Cinque Terra (but then there is luggage to deal with). We don't want to be running constantly. Maybe we will consider skipping Bologna and the Cinque Terra this trip. Would you recommend more time in Tuscany then? We would like to explore some wineries while we are there. Thank you for the thoughtful response.

Orvieto only has one car rental agency-Hertz
For more choices consider returning car in Chiusi- pretty close to Montepulciano and on the train line to Rome

We always book our cars with www.AutoEurope.com
They are a US based consolidator with excellent customer service
They no longer work with the Orvieto location due to bad service

Be sure to do your homework on driving in Italy-ZTLs, parking, speeding etc

All drivers will need an IDP ( International Driving Permit) which you can get at your local AAA for about $20

Yes, Jores I would recommend more time in Tuscany but then I am biased. My husband and I spend 8-10 weeks there every year.
We use Siena as our base. From there it is easy to visit Saint Gimignano and Volterra to the north and Pienza, Montepulciano and Montalcino to the south. And of course, there are winerys (and agriturismos) everywhere. You can search this site for "winerys of Tuscany" or do an on-line search. Most winerys require that you make a reservation in advance, so plan ahead.
Staying at an agriturismo is a great option since you will have a car. Sorry I don't have one to recommend but, again, searching this site will turn of many recommendations.

We will be taking train out of Monterossa and then rent a car someplace to spend a few days in Tuscany. I am looking at getting car at Pisa airport rather than going back to Florence to get the car. Does anyone have any input on where to get car and drop off coming from Cinque Terra, spending a couple days in Tuscuny with ultimate destination of Rome? I have only found one option of pick up in Pisa and drop off in Orvieto for over $700 for the two days with automatic transmission. (we will have 4 people). We would need to get train to Rome from drop off point. Thank you