May2015 Finally almost done with bookings

For a hotel in Rome, I recommend Hotel Smeraldo. It's in a great location (near Campo de Fiore) and reasonably priced. If you would rather be near Termini station, Hotel Diocletian is a good choice.

The area around Montalcino, Pienza, and Montepulciano is a good midpoint on the way to Rome, with plenty of Tuscan ambiance and sightseeing, whether you stay in one of those towns or a more rural agriturismo (with easy parking).

In the hilltowns themselves, expect a bit of a hike from the car park to a hotel or pension with your luggage. Here's what I've recently discovered about hilltown maps (for instance, in Montalcino): If a road looks short and direct, then it is straight uphill, perhaps even stairs. The flatter routes involve long switchbacks.

Have you considered spending 2 nights in Florence, and visiting Siena by bus for a one day trip from Florence. I found Siena to be very congested (down the hill), and parking very difficult to find.

You could pickup the car as you leave Florence, spend the night south of Florence in an agriturismo or small hill town.

Heading south of Tuscany, Orvieto on the motorway and it is a very popular hill town. The Hertz office is across the street from the Orvieto train station. Many drop their cars there and take the local train into Rome Termini--70 minutes.

Thanks for the feedback and suggestions everyone. I think I'll make a new post in the Italy forum since that is the only part of my trip I'm wavering on.