This route treats Istria as a region rather than a motorway detour. After a compact Zagreb arrival, Rovinj becomes a two-night base: one period for its harbour, St Euphemia lanes and Golden Cape, another for either Motovun's hill country or Pula's Roman remains. Trying to collect both on the same day creates parking stops and windshield time. Choose the inland food-and-landscape story or the southern archaeology story according to interest.
Sleeping near Plitvice changes the national-park visit more than adding another attraction. Drive from Istria in the afternoon, leave luggage at the accommodation and enter next morning at the reserved gate. A four-to-six-hour official programme can use boats and panoramic transport included with admission before the road to Zadar. This is more dependable than reaching the park from a distant city, walking at midday and continuing exhausted.
Zadar and Split provide the transition. Zadar gets two nights for Roman layers and a waterfront evening; Split gets three so Diocletian's Palace, Marjan or a beach, and one optional day beyond the city do not compete. Return the rental in Split. Dubrovnik's controlled historic access and scarce parking make a car burdensome, while an intercity bus finishes the coast efficiently. Four Dubrovnik nights support an early wall circuit, one island or coastal outing, a museum-led weather fallback and an unhurried departure.
The route omits an island hotel on purpose. A seasonal day trip can work from Split, but moving cases onto ferries would duplicate the ten-day island itinerary and add another fragile handover. Travellers who chiefly want Hvar or Korčula should exchange one Split and two Dubrovnik nights for an island base. Those prioritising food, road scenery and varied architecture will get more from this Istria-to-Dalmatia version.