We are wondering about traveling for 4 people from Florence to Orvietto by hiring a car & driver, instead of taking a train, and/or to do day trips from Orvietto. Any recommendations?
You might want to check out Francesco. I came across this recommendation while researching for my upcoming trip:
https://www.discovertuscany.com/tuscany-car-rental/tuscany-wine-and-drive.html
That site also has some information in general that you might want to look through.