3 of use are planning on spending 3 full days/4 nights in Rome after our Sicily tour and as we have all been before we are planning not on doing the biggies but some of the less well known options. One we are considering is Hadrian's Villa. If you have been to Hadrian's Villa did you enjoy yourself and how much is there to see? Enough to spend a solid portion of our day? We love history, ruins, and museums. Thanks!
https://community.ricksteves.com/travel-forum/italy/tivoli-day-trip-from-rome
Look at the last post, which is mostly about getting to Hadrian's Villa, but sheds some light on Villa D'Este as well. Having been to both, I put Villa D'Este ahead of Hadrian's for your first three trips to Italy. Doing both in one without a car and driver would be exhausting.
We never made it to Hadrian's Villa but that was our intent. We had planned to spend the day first at Villa d'Este and then Hadrian's Villa. The gardens and especially the fountains were unbelievable and we just ran out of time. The villa is certainly worth several hours and we will have to save Hadrian's Villa next time. It is easy to get to. Took the bus to Tivoli and train back to Rome.
We spent all our time at the gardens and fountains too. Such an amazing sight!
One of the most beautiful enchanting gardens in the world. Villad’Este !
https://europeanhistoricgardens.eu/en/portfolio-item/villa-deste-2/
I agree with others that Villa D'Este is absolutely stunning, but if you have the time, the nearby Hadrian's Villa is of another era. Well worth an hour or more detour if you have time. The statues around the water reflect the Roman columns and it's simply stunning. I drove with Italian relatives to both places so I'm not sure how you would get around with public transport, but if you've been to Rome multiple times, these 2 destinations would make a wonderful day trip.
Since you love history and ruins I think you’ll like Hadrian’s Villa. We stopped there on our way from Tuscany to Rome and spent 2-3 hours wandering around. I could have happily spent another couple of hours. The site is quite large. I was amazed that we could walk inside some of the ruins by the Canopus. A bit of research before you go will pay off when it comes to prioritizing which areas to visit and understanding what you’re seeing. Enjoy!