Rome is great have been a few times now, but beware of pickpockets & we actually got Jewelery stolen from our hotel room before we left, so leave everything in a safe until you leave, don't take it all out & leave bags in room while you go for breakfast... lesson learned
We have been to Sorrento twice and agree it is a good base to explore the area but we have enjoyed Naples. It is a city of character both dirty and clean with museums and catacombs. Amazing walks in the city centre.
We have never had any trouble there but don't wear jewellery!
The train meanders to Sorrento so take the fast boat if you wish but it is more expensive.
Bus to amalfi gives you some hair raising experiences but boat back is amazing.
Herculeam is better than Pompeii in our view and it is the same stop for Vesuvius so you can do both in one day. Private buses take you to the volcano.