We will be in Italy for 2 weeks, spending a couple of days in Lake Como, then renting a villa near Lucca with friends for a week, then exploring Umbria by car for 4 days & nights before training to Milan for home. It has been suggested that we stay in Orvieto for 4 nights as a home base and daytrip from there. Do we really want to stay there for 4 nights, or does anyone have a better suggestion? We do like to stay somewhere for at least 2 nights. We leave May 15 so answer soon!
I was starting to advise staying 2 places, but the more I thought about it, I think 4 nights would be nice. Two nights gives you just one day and then you need to move on. You can always take loop drives to small hill towns and still have at lease one day to just explore Orvieto and soak up a bit of Umbria.
We stayed in Vetralla - I think any of those small hill towns would be great for 2 days and you will be close enough to explore the area.
One can take train to Orvieto. There are car rental agencies at or near to train station there. I am not thrilled with Orvieto as a base as there is not a wealth of nearby sites. You might get a car in or near lucca, drive to Umbrian area, then drive car to Milan and drop it at airport. Accessing Milan airport and car rental drop is easy. One zone to explore is south of sienne, montepulciano,montalchino,Val d'Orcia, Sant Antimo. In Umbia you can train to Perugia, then take train north to end of line in sansepolcro, with many small towns along way, bus stop there is very near train station, take bus to hillside town of Anghiari (unique). Or take train or car to Arezzo and Cortona. Just some ideas.
If you want to explore Umbria, I recommend staying in or close to Perugia. It's a destination in itself, and it's close to Assisi, Spoleto, Gubbio, and many charming hill towns. There are many lovely B&Bs in the countryside near Perugia with quite reasonable prices. If you like Italian pottery, Deruta should also be on your list. You can e-mail me if you have more questions.