Best way to travel between Florence and Orvieto

Its a direct train. About every 2 hours from Santa Maria Novello and a 2 hour and 15 minute journey.

There are both direct trains on that route, as well as trains with one change. The direct trains will of course be easier, and you could consider departures from Firenze SMN at 09:09 or 11:09. Trains are often Regionale Veloce (DON'T forget to validate your ticket prior to boarding on the day of travel), travel time is ~2H:13M and current fares as low as €15:40.

You can see all the details on the Trenitalia website. When you arrive in Orvieto, take the Funicular from the station up to the main part of town.

The bus ride from the funivia at the top of the hill into the main piazza is free with your funivia ticket.

If you're planning to see several sights in Orvieto, take a look at the Orvieto Carta Unica. You can buy it at the newsstand in the train station. The round-trip on the funivia and bus is included.

As Chani states, the Carta is a pretty good deal, even if you are just staying overnight. I couldn't believe how much I used the card. They did give me the senior discount although I am not an EU citizen.

Thanks, all.