So many wonderful suggestions.
First off - we have never been to this part of Italy. We have been to Bellagio in the Como Lakes area as well as the Cinque Terre which we loved (stayed in Santa Margherita). We have been to Tuscany and love it and plan to spend a little more than a week there.
So, in planning the trip - my husband has not been to Rome, thus some time there. Since we may not get back to Italy (too many things on our bucket list), we thought we should allow some time to explore the AC. Your suggestions regarding Sorrento make sense.
Typically we try to avoid the crowded tourist towns but I do want to see Positano and the AC area. I have heard Ravello is beautiful as well. Additionally, we like to combine our trips with some history as well as some time to soak up the local culture. We don't need to sit on the beach. We go to the Caribbean for that :) Additionally, we aren't big shoppers so that is not our focus.
I love photography and take many photos of the landscape. That being said, I also wondered if we should go to one of the other islands, Procida or Ischia (?) rather than Capri. However, the grottos intrigue me but again, with the little time that we have we would not be getting in the water more than likely. So, the idea of a boat trip around the island sounds like a good idea.
I have always thought that a trip to Pompeii or one of the others you mentioned would be interesting. We only really have three full days and possibly a half day. My thoughts are
1) one day for Capri or one of the other islands
2) one day for Positano and the Amalfi Coast possibly Ravello
3) Pompeii etc?
We are looking into the train to and from Rome/Tuscany although I haven't booked anything yet.
I hope this helps you offer up better suggestions.
P.S. If we are spending the day in Positano/Amalfi Coast and staying in Sorrento are there transportation options back that would run in the evening?
FYI, we have been to Greece and Turkey and seen many Greek ruins.
From here, we will be heading to Tuscany.