hill towns with limited mobility

Flat- Castellina, most of Panzano, Radda, Greve, Pienza, Lucca.
Once you drive to the top of Volterra and park,
it is pretty flat.

My wife was in a wheelchair on last year's trip. She had a knee replacement a year ago, and we recently ran all over the Barcelona, Paris and Madrid Metro systems without her having any walking problems.
I would just say drive your sister as close to the city center and then go park the car. You can minimize her wheelchair riding somewhat. You just have to watch for the cities with the cobblestones in Italy.
We have been surprised to see so many Spanish cities with sidewalks and Metro systems prepared for wheelchairs.

Rick's guidebook will include a general description of the terrain and parking options for each town, which should give you some clues, though not tailored specifically to your needs. Many have some bus service, though they might not be fully wheelchair accessible. In less busy destinations, some parking and ZTL limits can relaxed in the low season, indicated on signs.

Many towns have a central road that's relatively flat and well paved, as long as you can get to it. If you look at maps, assume that long switch-back roads are relatively flat and more the direct roads/paths are steep. Google Earth could help you see terrain. Also try each town's tourist information office, which may have more specific advice and maps online.

General thoughts from memory:

• Umbria: Orvieto can be reached by funicular plus bus from the train station and parking. Assissi has a shuttle bus from or near some parking lots; the Basilica is at the lower end of the somewhat steep main road. Gubbio has three elevators that take you between some of the levels, and has flat switchback roads. I'd avoid Cortona.

• San Gimignano is not very steep for perhaps half of it; also has a shuttle bus.

• Montalcino has parking near the Fortezza that puts you at the top of the town, which has a fairly flat road/spine along the top of the hill. Other parking lots require stairs.

• Montepulciano's main street runs up/down a pretty steep hill. There is a public shuttle bus along the route.

• Massa Maritima - A few years ago in October, I was able to park pretty close to the main square.

Suki gave you a great list.

Siena and San Gimignano are out of the running.

I believe there is an elevator from the underground parking at Volterra.

Greve would be very easy to navigate, but it is not technically a hill town. There's no ZTL there, you could drop off your sister and then scoot across the street to the free parking lot.

Sent you a private message. I too travel with a wheelchair.

Thank you to all who sent great info. I really appreciate it.

Please keep in mind that getting to the town is not the end of the challenge. Many of the sites you want to see will have steps to climb and no options for anyone in a wheelchair.

When you have identifed what you want to see, be sure to research the site to see if there is any kind of an elevator or special lift for a person in a wheelchair.

The same goes for lodgings. You need to pay close attention to how accessible they are. The ground floor may be up a few steps from the street. Once inside, if there is one, the elevator may be up a few steps from the lobby or ground floor. It may also stop before the top floor, so there could be more steps up to the top floor. Walk-in showers may be best for everyone. Italian tubs tend to be deep and narrow and hard to get into and out of. In either case the floor or tub bottom could be very slippery. Non-skid shower or water shoes can be a help with that.

Restaurants occasionally have a handicapped toilet on the main floor, but it's more common to have to go up or down stairs to get to the toilets.

As others have hinted, riding in a wheelchair over the very common cobblestones will be a teeth-rattling, kidney-jarring event. Likewise, do not even consider going up or down any slope in that portable chair. It's much too dangerous. The last time I was in Italy I had some serious knee issues and I didn't walk up or down slopes unless they had a handrail.

Needless to say, if the only option is stairs, with or without a handrail, the wheelchair will be useless.

I'm being a Debbie Downer, I know, but I think my experience with cranky knees is relevant. They slow me down and limit my mobility significantly, but if the sister has to use the chair all the time, she (and your group) may have some organizational adjustments in what you can see and how you can see it.

You may have a heavier load of research to do than most to make sure that things are the best they can be for her and the rest of your group. I know someone who went to Italy about 5 years ago when he was about 70. He'd been wheelchair-bound since the age of 25. He and his much younger fully mobile wife found Italy, even Rome, highly inhospitable for a person in a wheelchair.