Great part of the world.
We’ve stayed in Sorrento twice – and love it.
Easy to get to from Naples, we took the train, which goes past Herculaneum and Pompeii on the way.
Both sites are awesome and well worth visiting – however Pompeii can be hard-going if its really hot as there is very little shade.
Herculaneum and Pompeii are both worth a visit, but like you said, don’t do guided tours as they are very rushed to try to fit it all in. Your much better going in on your own and picking and choosing the bits you want to see.
+1 buy a guide book rather than guided tour.
We didn’t think much of Naples but to be fair we didn’t try very hard to get below the surface.
We took a coach/bus from Sorrento to Amalfi – amazing route but possibly the most travel-sick I’ve ever been.
Capri is great – there is a jet boat/hydrofoil thing that’ll get you over there quicker than the ferry.
The Grotto Azura is worth a visit if you are going to Capri.
We will be going back as soon as the kids are old enough to appreciate Herculaneum and Pompeii.