Italian insights....
Venice. Spent 2 nights there a few years ago around a cruise we took Pretty magical town but pretty sure I read recently they're starting to charge day trippers an extra charge. Another instance of 'we're getting tired of tourists' I suppose.
Spent a week in a villa in Positano. Amalfi coast is a must see. Hired a private driver to take us to Pompeii, Sorrento etc. Took the train from Naples to Rome for a few days. Rome was okay for me but crowded and seemed moreso after the week in laid back Positano.
Always book Class 1 on trains over there. We have always found that to be better than Class 2.
Took some friends with us last year and based out of Sorrento. Rented an apartment a bit away from the city center. Hired a tour company so our friends could do the Amalfi coast and Pompeii. Fell in love with Sorrento! Easy to get around, amazing food choices. We took the ferry to Capri for the day. If you do this its recommended to take an early ferry as it should be less crowded. Capri is pretty cool. Took a convertible taxi up to the top. Great views.
There are plenty of reputable tour operators to utilize. We have never had a issue with anyone we used.
This year I met the wife in Munich for an Adele show then flew into Naples and hired a driver to Sorrento. This time we stayed just off Piazza Tasso. Excellent location! Visiting the Fauno Bar is a must. A lot of shops, restaurants etc. in this area. Also easy to get down to the port for ferrys.
We did zero touristy things this trip. Chilled at the hotel pool, sat at outside cafes people watching with drinks and snacks.