Spend the first evening in Split, then travel south through Hvar and Korčula to Dubrovnik. Three ferry journeys link four overnight stops, with no return to Split at the end. The six-night plan includes arrival and departure days, so an early arrival in Split gives you more time among the palace streets.
Hvar has the only full island day: choose a boat outing or a visit to Stari Grad. Korčula is a shorter stop, with enough time for its compact Old Town and dinner by the waterfront. Dubrovnik gets two nights so the walls do not depend on your flight time. This is a week of historic towns and short sea crossings, with swimming when conditions suit. For several unhurried beach days, spend the week on one island instead.