Car Rental in Rome

I would suggest that you not rent the car right in the middle of Rome. Consider picking up your rental at the Roma Tiburtina rail station. It's on the east side of the city, so it will allow you to avoid some of the city traffic.

Could not agree more, renting in central Rome will be more trouble and more expensive than it needs to be. Make sure you are really comfortable with manual driving.

Different companies have locations at different spots near Tiburtina. But the Tiburtina locations are best to head out to Abruzzo.

www.autoeurope.com is my recommended broker. They work with all major companies.

Learn road signs ( see the Wikipedia article on Italian road signs)
Learn about ZTL (AutoEurope website above has a page dedicated to it).
Get an IDP at AAA (mandatory in Italy)

We rented a car in central Rome on a SUNDAY MORNING, and drove out. I would suggest the same for reduced traffic. No memory of where we rented but download Apple and Google maps of the area you plan to travel to, prior to your trip, as you won't need wifi to access your maps when previously downloaded. Also check with your credit card company to see if the car insurance they often cover with rental cars is valid in Italy. Learn enough Italian and laws to be able to effortlessly travel Italian highways. Most European rental cars we've experienced are standards, not automatics.

We have never not been able to rent an automatic in Europe-France, Germany, Italy

I don’t think any credit cards cover insurance in Italy
Maybe Amex for an additional fee?

We always book No Deductible, Full Insurance = peace of mind for a few euros more

As many users here recommend, we always use auto Europe, link in one of the recommendations of above. Do it in advance and the farther in advance you do it the less money it is.
We found it easy to rent right at the central train station, it was not stressful getting out of Rome.

Did this twice and plan on doing it again this spring.

The only hard part was one time we returned the car to Rome and that was a little more difficult with traffic, etc. but getting out of Rome, no problem.

The toll road through Lazio and Abruzzo, known as the Strada dei Parchi, is absolutely glorious. Mountains, valleys, medieval hill towns, an amazing demonstration of Italian civil engineering skills in the bridges and tunnels…you will enjoy the trip. I agree that Tiburtina is a good rental location for getting out of the city quickly.

Your other option is to take a lovely coach bus from the airport or from Tiburtina and enjoy the road in comfort. Then pick up a rental car in Chieti or Pescara. Or even Avezzano if you don’t want to backtrack to Abbateggio. I live just up the road from Abbateggio, and I rarely drive to Rome. I leave my car at the bus stop and let someone else do the driving.

Coach companies include Prontobus, Clikbus, Flixbus (all stop at Chieti Scalo) or DiCarlo bus (doesn’t stop till Pescara.)

Whenever I pick up a rental car at a Tiburtina station location (Avis-Budget, Europcar, Sixt, and Hertz are all in the same block) I head to the A24 freeway, the freeway that goes to Abruzzo, even though a later take the GRA toward Florence. I find it easier and often less congested to go that way rather than the Circonvallazione Salaria, which is more direct for me to drive to Tuscany.

To guide me from the rental agencies (no matter which) to the A24 freeway (the one you want), I first set up my navigator to guide me to this freeway rest area, I saved on my GoogleMaps favorites:
https://maps.app.goo.gl/Q6VXhtxbrPo4oBdG8

Then once there (I'm already on the A24 freeway at that point), after stopping for an espresso or macchiato at the Autogrill, I proceed to my intended destination resetting my navigator for that destination.

Do the same and you'll be fine.

There are few freeway drives in the world that are as beautiful and majestic as the A24/A25 freeway from Rome to the Abruzzo coast. You'll be inside very long tunnels occasionally, but otherwise the views are gorgeous.