You could checkout what www.vrbo.com have to offer

www.discovertuscany.com

Car rental www.autoeurope.com.au

Route planner www.viamichelin.com

You will require an International Driving Permit for Italy, and read Top Questions to the right "Driving in Tuscany" to inform on traffic restrictions and ZTL areas.

Local buses www.trainspa.it

www.busfox.com/timetable

Trains www.trentitalia.it/homepage_en.html

tripadvisor.com/…44800634

Someone asked something similar recently and I replied with a recommendation (see link above that will take you to the conversation). There must have been six couples (right Joni?) who rented this place and their initial plan was only to hire maybe one car as there is some public transport in Sarteano including a bus to Chiusi station (15 mins away). But once they'd arrived they had a change of heart and rented more vehicles for you really do need a car in southern Tuscany, irrespective of where you stay. Something I didn't mention on my earlier post is that one of the restaurants just a few yards from the palazzo they rented offered informal cooking classes to the group where they even learnt to make pici. That's the joy of staying in a small, less well-known village such as this one, it's an altogether far more authentic experience. (And it's a world away in atmosphere from Cortona in summer and far less crowded.)

I really think you will need to have rental cars. Many, many people look for villas that are within walking distance of a town or village, but there are few that are and even if it seems walkable on paper when you get there you may discover it is not practical. The route is often steep, perhaps involving a dirt track at some point. There is unlikely to be a pavement or street lighting making walking home after a meal unsafe at night.

I frequently holiday in summer with a large group and find that trips to the supermarket need to be taken nearly every day for something or other and lots of shopping is required. You need a car to transport it all.

Being near a train station is most useful for day tripping to cities. However getting to smalller towns and villages is frequently either not possible or you arrive and find that the station is some distance from your destination and you need to wait for a bus to take you there. Local bus services serve the local community's needs and so run mainly to fit with school and work day times. You will find yourself seriously constrained in where you can go and when if you rely on public transport.