A common shape is two nights in Barcelona, a week-long sailing calling at ports like Naples and Rome (Civitavecchia), then a few nights in Rome before flying home, a city-and-cruise trip that makes the most of both.
Three ways we’d do it
Fly-cruise · 10–16 days
Barcelona + Mediterranean Cruise
Fly to Barcelona, settle in for two nights, then sail the western Med.
Barcelona → Naples → Civitavecchia → Rome
Coastal escape · 7–10 days
Amalfi Coast Escape
Naples, clifftop Sorrento and the lemon-scented villages of the Amalfi Coast.
Naples → Sorrento → Amalfi Coast