I didn't make time for Sorento, Amalfi Coast or Capri. My trip was one night on the plane on the way to Rome, 13 nights on the ground, train to Florence the same day my plane arrived, 6 nights in Florence (I could have cut my time in Florence down to 4 or 5 nights); day trip to Pisa using the train; Train to Naples, 3 nights in Naples. 3 nights was enough to see the art museum that almost nobody goes to, in Naples, the day I arrived, Pompeii in one day and the archaeology museum in Naples on another day. Then Train to Rome and 5 nights in Rome. There is enough in Rome that you could spend more time there or pick what seems like the most important places and acquiesce to skipping other places. I did a guided tour with a tour called "The Roman Guys" but now I realize that I spent too much time paying attention to the tour guide and not enough attention to the environment and the ruins. The tour guide was plenty smart or knowledgeable enough and now I perceive that some background reading and just the normal tickets where you tour the sites unguided would have been good enough. My plane back to Detroit left from Rome. I didn't rent a car in Italy. I own a car and drive in like an average person, in the Detroit area.
You know your son's temperament and behavior and whether he will just go along with whatever you want to do or whether he has specific interests you want to accommodate, and so on. My parents didn't take me far from home. My mother has had a lifelong phobia of riding in a plane; she has never taken a plane flight. I have traveled to Europe 7 times so far in my adult life, all solo trips.
Edit: in Pisa there is a museum I went into, by the leaning tower, that almost nobody goes to. If you visit the museum, they let you use the bathroom in the museum. If you don't want to see the museum, you have to wait in a long line for the bathroom the average tourists use.
I doubted Brunelleschi's brick dome on a church in Florence, would be appealing, because I wasn't raised Christian. But I bought an advance ticket anyway. But then a machine showed that my ticket was "already used that morning". I suspect that what happened was, I accidentally showed my ticket for the dome at a previous museum and the wrong ticket worked at the wrong museum anyway but then the ticket for the dome in the museum organization's computer system registered the ticket as "used", because many of the museum tickets are all sold by the same organization; make sure you print your advance tickets and pay close attention to make sure you show the right ticket at the right museum.
