Day Trip to Orvieto

It's an easy day trip from Rome on the train and really worthwhile, a beautiful hill town. For a restaurant, La Palomba (the dove). See if you can find the picture of Rick Steves on the wall. Don't miss the cathedral.

Sounds like a great idea - I loved Orvieto. Here’s a link to my report of a trip in which it was the first stop: https://community.ricksteves.com/travel-forum/trip-reports/report-orvieto-siena-ravenna-venezia-late-december-early-january
When you get off the train, you can cross the street to a funicular to ride up the hill.

Rick covers Orvieto in his guide to Italy, though not in the guide to Rome--an odd decision. Orvieto has quite a number of very worthwhile sights; it's not your standard hill town where you'd spend an hour or two walking around and be ready to leave. There are some good museums. The tourist office used to offer at least one walking tour. As of 2015 there was a T.O. near the train station.

It's been years since my visit to Orvieto, but at that time (and for years before that), the funicular only ran until 8 pm. If you're planning on dinner and a late train back, be sure to check the times. There may be bus service to the train station, otherwise a taxi should be available.

The TI at that time offered an underground tour that was excellent. If that's not available there are at least a couple sights to explore the "swiss cheese" of Orvieto - one was an ancient winery, if memory serves.

The loveliest thing I did was to sit on the bench opposite the Duomo in the late afternoon and enjoy the changing colors of the facade as the sun sank . . . even better with a gelato.

Did you see this already? https://community.ricksteves.com/travel-forum/italy/one-day-in-orvieto

Orvieto is a beautiful hill town. A day trip there makes me want to cry, it is too nice for such a quick trip, the charm is at night and early morning. A first trip to Orvieto deserves 3 nights, subsequent trips 2 nights would work. I have been 7 or 8 times and will go again this October. There is a great place to eat just down the alley from the main Duomo, Etruscan something or another, just delicious food.

Do we need to get train tickets from Rome to Orvieto in advance?

No
Regional trains can’t sell out and price never changes

This is what we did in one very relaxed day in May this year, but as Joanne said above, you could easily stay longer.....
https://slowtravelitalyspain.blogspot.com/2023/06/umbria-in-may-orvieto.html?m=1

Most of the trains traveling between Rome and Orvieto are regional trains, but there are a few InterCity trains. They aren't significantly faster, but the fares on those trains vary with demand. On regionale and regionale veloce trains the round-trip fare will be €18.30 for adults.

I thought the guided walking tour that went under the city was cool as heck

I concur with ponygirl1813 in recommending Trattoria La Palomba. Reservation wise.

We had considered a day trip to Orvieto and figured we would wing it on the day of as we have some experience with trains but this would be our first on a regional. Well today is that day and for the first time ever we missed our train in Italy! I did a small amount of research here on the forum but didn't dig deep enough to find the warnings to allow extra time if the train departs termini from 1est or 2est … well you can guess it was and even with 5 min to departure as we passed through security, about half way through we saw people start running… shoot, ‘is it really that far?’ I thought to myself. Well, it was and once we realized and started running about half way down, it was too late.
Fortunately we were able to figure out there was one more morning train and that we could take the metro to tiburtina, where we could then catch the next train to Orvieto, utilizing our same tickets. It was a bit of an adventure and actually forced is to use the metro (first time for my hubby).

so lesson learned for cutting it so close we should have built in 10-15 extra minutes.

The loveliest thing I did was to sit on the bench opposite the Duomo
in the late afternoon and enjoy the changing colors of the facade as
the sun sank . . . even better with a gelato.

Absolutely, Chani! I have pictures that the glass looks almost neon. Also, if you're facing the Duomo, walk down the path to the right to the overlook of the beautiful valley. You may be befriended by numerous well-fed cats. It's a sight not to be missed.

One day? Spend time in this magnificent little town. We spent 10 days in an apartment with views of the Duomo! It was magical to stroll the town and find one more amazing place to eat! Then wander the streets with the towns people at night, sit and enjoy a gelato or glass of wine. Make some painted paper! I wish I could recall all the names of the restaurants we found, but we just got lost in the pretty streets day after day.

One of the things I love about Italy is all the great hill towns. The problem is deciding which one. Orvieto is a great one to visit. Sadly, I only had time for a day trip. I spent the month of September in Arezzo and visited Orvieto on a whim the last weekend there. I wish I had time to stay longer. But the great thing about that is it goes on the list for "the next time". I found the local brewpub and highly recommend it if you enjoy good craft beer - FE3.0 (FEBO) -- Via Gualverio Michelangeli, 7, 05018 Orvieto TR, Italy.