We will be flying into Venice on July 2, 2015 for two nights then picking up a rental car from Sixt. We would like to drive down the Croatian coast (3-4 days) to Dubrovnik (2 nights) then take the overnight ferry to Bari and finish with a few days in Puglia before flying home from Naples (July 17, 2015). Sixt will allow us to bring the car to Croatia and has no restrictions against taking it on a ferry--although the ferry requires that we have "original documentation" and explicit permission for the car to travel.
Has anyone done this route (or the route in reverse from Bari to Dubrovnik) with a rental car who can advise re: logistics? Has anyone tried the ferry crossing with a rental car and did you have trouble? Has anyone been able to get proper documentation from Sixt? We don't feel comfortable making lodging reservations in Istria or even Dubrovnik if we're going to get stuck in Dubrovnik with the car.
Another option might be to drive from Venice to somewhere in Istria for a few days and then drive down the Italian coast, leave the car in Bari, and take the ferry sans car for a round trip to Dubrnovnik (lodging would be on the ferry [not ideal but manageable]).
We would love to hear your thoughts and recommendations. ~Jack and Kathrine A.