'So Naples and Sorrento it is, then.'

Not a good combo IMO :(

Amalfi should definitely be one of your choices
(- or somewhere on the Amalfi Coast i.e. Amalfi, Positano or Praiano),

- so I'd say

Amalfi + Sorrento or
Amalfi + Naples.

Steve

I agree with Steve!

So do I

Munna,

I also agree. Napoli and Sorrento share the same transportation systems, practically the same neighborhoods, so there is no point in relocating. Amalfi is remote, plus the scenic jewel of your picks, so you want to see the sunsets there, etc., and base there rather than daytrip.