I'm a little bit confused about the length of the route. Originally it was 60km, but it somehow got shorter while riding it. I might have added some waypoints that in the original plan added to it.
As mentioned, biking in Rome seems to be actually just fine. Generally, I found that the Italian drivers are actually pretty courteous. I hope I'm not jinxing it, but when I compare it to Berlin or Brandenburg it's definitely more civilized. What might help is that the cars are generally smaller, hardly any SUVs on the road.
The bikelane along the Tiber was great, and what was even better was to see some other bikers along the way. In Brindisi I haven't seen a single rider. One thing to note if you plan to take this route. You should check where it's easy to actually get on it within the city. Mostly it's stairs and you don't want to do that with a loaded bike. In my route I take a ramp which I've known from before.
I had a chat with three old Italian guys which was great, but bumpy. My Italian.
All in all, nice landscape, uneventful, instilled some confidence. Didn't crash with any dogs. Plus, I was greeted by a super nice host, who made me coffee and who's driving me now to the local restaurant. Cacio e Pepe!