Have just booked a holiday with a friend, a drinking buddy for want of a better way of putting it

We are staying at Sorrento, iether at the Dania, Ascot or Villa Maria -AOA with Voyage Jules Vern. Have loads of questions so here goes. Depart 17 June for 7 days.
Never used the company before so any comments would be useful.
Have booked two trips, one to Pompeii and the other Amalfi coast tour return by boat via Naples. Both with VJV as we don't know the erea. Comments again would be helpful.
We both want to try and make Rome for a day if poss, again new to us. The buses take too long by the look of it and by car, well with traffic and parking problems, think thats a non starter or is it?
The train looks a lot better and only about an hour and a half each way by Trenitalia. E39.00 each way, but can't work out what station it arrives at from Naples. Or is there a direct train from Sorrento?. We will be pushed for time and would have to be selective on what we want to see in Rome. I think the Vatican is a must, but do you have to Queue for hours to see the Sistine Chapel?
I Don't take travellers cheques or currency away anymore, just use Visa Debit card - no transaction charges and top currency rate. Is this suitable for this area?
Sure I have more questions but can't think of them at the moment.
Lovely to see the site still up and running and well.
Peter