Early stages of planning trip in September

I would change it up a little to eliminate a hotel change.

Upon arrival take the train to Orvieto, get rental car. Spend 4 days exploring.

Take train back to Rome for remainder of trip.

This eliminates one change of hotels.

Never buy a rail pass for Italy. It's much cheaper to buy point to point tickets 120 days in advance. Rail passes never save you money. Why would you need a rail pass if you have a rental car? I would choose either to use the rental car or ditch the car and just use the train.

I would appreciate any thoughts on where to stay in/near Orvieto/Venice

I'm totally confused by this statement. Orvieto is no where near Venice. You don't mention Venice at all in your initial itinerary so I'm really confused by this. Use booking.com to find hotels in Orvieto and Rome.

Just my opinion but scrap your second itinerary. 2 nights does not equal 3 days, it equals 1 full day and 2 partial days. Basically you'll be giving yourself a day in Rome, 5 days in Sicily and 2 days in another location before heading back to Rome for your flight home. It's too much travel.

Donna

Sicily really needs more time than you have; it is a large island. Therefore, I strongly favor your first option.

I am confused about the reference to Venice, though. How does that fit with traveling between Rome and Orvieto/Umbria?

Orvieto is a lovely town and not small as hill towns go. It has a very pretty cathedral and a couple of interesting museums (not terribly large or overwhelming, but also not as important as the options in Rome). It is a lovely place just to wander around, though it gets quite heavy day-trip traffic (much of it Italian). I suspect it's less crowded on Monday-Thursday. Although it would not be as convenient with a car, I think I'd like to stay in the historic center rather than out in the country where I'd have to drive to go somewhere for dinner.

In any case, I suggest going on to Orvieto the day you arrive. You'll be sort of jetlagged anyway, and Orvieto is a much more laid-back place than Rome. You can wait until arrival to buy your train tickets to Orvieto, so you don't have to stress about how quickly you'll get out of the airport. You can spend the rest of your arrival day walking around outdoors in Orvieto, trying to adjust to the new time zone. Plan to pick up your rental car the next day. I have never rented a car in Europe, but I believe people have reported that Hertz has a location in Orvieto but that you can't book for pick-up there through AutoEurope.

If you do end up including Venice, I suggest flying into Venice and out of Rome if you can snag an affordable fare. That will prevent your having to return to Rome for the flight home. Venice is generally considered a non-optimal departure point because flights connecting to transatlantic itineraries leave at very early hours, thus my suggesting to fly into Venice and out of Rome rather than the reverse.

Just a suggestion, as soon as you arrive in Rome, take a train to Florence either rent car there or go to Orvieto by train and rent your car there to explore. Then see Rome when you are adjusted ( a bit) to the time zone at the end of your trip. It seems like you have 8 nights? Seeing Rome in two segments doesn't make sense to me. I have arrived in Rome, had a coffee and light lunch at the train station just to wake up :) then get on your 1-2 hr train ride to wherever you are going...by the time you will arrive it will be check in time for most hotels! Paying $ to stay in Rome in two segments doesn't make sense to me.

Oh geeze. I do not know how I completely forgot Venice. (and this is why I am here - needing a lot of help)
Above revised: Day 1 arrive Rome. Day 3 depart by train to Orvieto -once there, car rental pick up and returned on Day 6 .
From Orvieto, train to Venice for days 7-10 Returning by train back to Rome, leaving home next day.
If there is a better option as to where to pick up the car rental. I am open to other places to use as home base for a few days -it does not have to be Orvieto.
We could quite possibly return to Chicago from Venice. However as it stands now we would fly non stop to ORD. This allows just a little less air travel.

Thank you for your patience and all of your help.

Have to agree with Donna and Acraven, arrive Rome (FCO).

If you don't drive a stick shift, you may need to pick up car at the airport, otherwise...

Take the Leonardo Express to Roma Termini 30 min. Then the next available train to Orvieto.
Spend 1 night

Rent your car here when you're ready to leave.

Travel around Tuscany basing in one town for 3 nights.
Which towns do you want to visit?

Drop your car at Florence airport, bus 6E or taxi 22E into town.
Spend 3 nights.

Train from Firenze SMN to Roma Termini 90 min. Spend 3 nights.

Trying to throw Venice into this mix is just crazy! It's 265 miles from Orvieto. 4 hours driving.
If you just have to go, do it as a day trip from Florence.
Train, Firenze SMN- Venezia Santa Lucia. 2 hrs 05 min.
This would be a very long day.

For driving in Italy you will need an IDP, international driving permit, available at AAA
Cost is around $20.
Learn Italian road signs, and
ZTLs.

For a quick look at drive times between cities check out Rome2rio.

For printable maps use Via Michlin.

For trains use Trenitalia.com.

Venice as a primary location changes the path you should take.

Fly INTO Venice.
3 nights

Train to Florence.
3 nights.

Rent car, drive thru Tuscany to
Orvieto. Drop car
1 night.

Train Orvieto- Roma termini
1 hour 17 min.

3 nights Rome

Fly home.

My biggest issue with your plan assuming Venice is the Day 7-10 is the lack of time for Rome itself!
Your first day you will be tired and jetlagged. So excluding that night ; you have only 1 night in Rome with this plan.

Gerri's plan is very good for the places that you want to visit. When structuring your itinerary, plan to lose a half day every time you switch locations. I feel like you don't have enough time to explore Rome; it's a powerhouse of awesome sights. If you can possibly add a night to your trip, turning it into 11 nights instead, I would give it to Rome.

Thank you so much for your help!

Gerri gives good advice. If Venice is top on your list start there! Just don't stretch yourselves too thin, you will think of traveling as a chore..you want to relax a bit! Building in an extra day or two makes a lot of sense for all of the places on your tour list.

I most heartily agree with the "straight line" plan suggested earlier. Fly into Rome and out of Venice ( or reverse it if it works better for flight arrangements).

With the number of days you have, you do not want to spend one day backtracking to catch a flight.

I'm curious about the time in Orvieto - unless you have an undisclosed reason for visiting there, I would skip it and add that time to Rome. Really do your homework on renting/driving a car. We're glad we did but it's not a "walk in the park".

Thank you all for your replies - you have given me much to think about.
we will be flying direct in and out of Rome , so returning back to the states from another city is not an option.
Orvieto was originally chosen for the ease of getting there from Rome without a train change. However we have since decided to spend the majority of our time in the Tuscany region before heading to Venice for the last few days of our trip. Because we will have to fly back to the states out of Rome it means backtracking but I don't know how to get around this.

My questions are-
Am I correct in saying it would take 2 trains to get to Siena.
Would you suggest using this as our home base and for car rental pick up and return? Taking the train from there to Venice before we return to Rome?