PalenQ

Britain still has the very worst rail system in Europe overall that I've been on - or one of the worst - better than Ireland, Portugal and some of the old East Bloc - but never ever up to par with the likes of France, Germany, Spain and yes even Italy, which has key true high-speed rail lines linking main cities.

ElizabethMinchilli

You're right, the 11:23 is the earliest train that will work for you from Orvieto, after dropping your car. There used to be a lot more trains all during the day, but the service was cut back a few years ago. Now most trains serve commuters, and so leave too early for you.

I always tell people not to drop off their cars in Rome if at all possible. Driving around Rome can be a real nightmare if you don't know where you are going. Another option would be to drop your car at the Rome airport, then take a cab into town

One word of advice: If you do end up taking the train into Rome, be very careful in the Termini Train station. It's become very bad lately regarding pick pockets and even theft of luggage. Keep your eyes open, and don't accept ANY help from ANYONE getting off the train.

PalenQ

You can avoid Termini all together by getting off the train at Rome Tiburtina station, just before Termini by several minutes and hop the metro or cabs there - about the same distance from many hotels as is Termini and none of the dicey things Elizabeth warns about in her above warnings about Termini - my take too on that!