10 days in Italy -- Itinerary Help

You could arrive Rome, head to Naples, spend as many days as you wish, head to Rome and finish there.
Insert Orvieto in the middle if you wish, but you could definitely fill five days in Naples and environs. See train schedules on the Trenitalia and Italotren websites to see what works out better.
A lot depends on where are are flying from and arrival time, but I prefer to not split stays unless I have to. It maximizes your time to limit hotel changes.
I would leave on Saturday--we always leave one day for "recovery" and more time is always worth it!

It would save you time to fly into one city and out of the other. We chose to fly into Naples, because flights home from Naples were early in the morning.

For Naples, Take a look at Hotel Piazza Bellini. Loved it, great breakfast.

We absolutely loved Orvieto.I'd recommend staying there at least two nights. Take a look at the train schedules in advance. The RS guidebook gives the impression that it is a quick train ride and the trains are frequent. You will find that not all the trains are direct. I would advise not doing Orvieto on a day trip. The logistics are such that you wouldn't have the amount of time you'd like. In Orvieto, we stayed at La Magnolia.

Oh boy! You've entered the forum's favorite area! A few questions: where are you flying from? Have you been to Italy before? If so, where did you go? I really like your husband's preference of parking himself for at least 2 nights.
If you are primarily interested in Rome and Naples, maybe fly into Naples and home from Rome. Yes, it may not (right now) look like it saves much money, but it does save some time which is very important. While in Naples you have pretty good access to Pompeii, Herculaneum, Sorrento, Ischia and Capri. A bit further, and longer trip, is the Amalfi Coast. That's a hefty bucket list and I didn't even mention Naples! Rome also provides a huge list of 'maybe I really want to do/see' things. But a day trip to Orvieto (easy by train) isn't a bad thing to consider. So, now you are looking at a very filled and very exciting vacation in Rome. You're right - you'll need recovery time before returning to work.

I say go for it! Do your homework now about flight schedules, 'must see, must do' things in each place, and hotel/apartment locations in each city (to cut down on commute time within the city). Do the work now and you'll have time to sleep and eat while you are in Italy. Honestly, I think many first timers don't expect the abundance of opportunities for amazing experiences Italy has to offer in each city, town, region, piazza. Rick's guides can be a great help. This forum too. Enjoy the planning!

If you depart on Saturday that gives you 10 nights. Always give a trip as many nights as you can.
We have found multi-city/open jaw flights to be about the same as roundtrip- or if a difference usually negligible. Be sure you are adding up all extra transportation costs and time.
Each location change eats up at least a half a day.

You need to be in your departure city night before flight so if you fly RT Rome- you should end in Rome. On arrival take fast train to Naples- 4-5 nights there- then fast train back to Rome for the remaining 5-6 nights.
If you are flying from Calif this could be a very long travel day!

Orvieto can be a day trip from Rome.

Or fly in to Naples- 4-5 nights then fast train to Rome for remaining nights. That’s one fast train journey vs two if you fly RT Rome.
Or Naples 4 nights-train from Naples to Orvieto for 2 nights then back to Rome for 4

Another option is split stay in Rome- wouldn’t be my choice but you could
Rome 3 nights
Train to Naples- 4 nights
Train back to Rome for 3 nights.
You could stay in 2 different neighborhoods- plan your sightseeing accordingly.

I also suggest you go to the Naples area first. If you fly into Rome you must hop on the train and get off at the Roma Termini station where you’ll need to transfer to get to the Napoli Centrale station in Naples. To get to the Amalfi Coast, you’ll need to take the Circumvesuviana commuter train that you will catch in the basement at Napoli Centrale. Sorrento is the end of the line and makes a good base to explore the coast.
I agree that a day trip from Rome to Orvieto is best. Changing hotels is a hassle and the less you unpack and repack the easier it is. Five nights in Rome is good. I also agree that you should fly home on Sat. That’s what I do, allow two nights at home before returning to work.

Maybe day trips from Rome to Orvieto used to be easy. It wasn't when we were in Italy this past February. We sat in Rome Termini for at least 2.5 hours waiting for a train. We had to connect in Orte to a bus to get to Orvieto and from there take a funicular up to the old town. Even then, the funicular is at least 3/4 of a mile from town center. There are some direct trains between Orvieto and Termini or Tibertina, but not hourly. We met a couple returning from a day trip on the 3:30pm train. That was the only direct afternoon train. They were disappointed and felt they had had very little time to explore Orvieto. Strongly urge an overnight. This also allows for time to explore the city with the day trippers gone.

Please at least look at the train schedule before committing to a day trip.

Thanks for all quick responses. I'll ponder them all, plus dig around in this Forum and Rick's latest Italy guidebook. This is our first trip to Italy and of all the many options, Rome & Naples interest us the most which is how we narrowed our focus.

I'll definitely look into flying into one city and home from the other. To answer someone's question, we'll be flying from Sacramento.
Any thoughts on when to actually book flights -- how many months out? (We've been to Europe before and depending on the trip we booked anywhere from 2 months to almost a year in advance)

I do think we'll stay until Saturday -- I'm not really sure why I didn't really consider that before.