Is it best to fly into one airport then depart from another? Plan 2 weeks or 2.5 and to drive there
That also depends on which islands in particular you want to visit. There are heaps of beautiful islands further up the coast.
Croatia Airlines is a part of Lufthansa's Star Alliance group, so you can also combine flights with other airlines from the same group and use their codeshare. Than makes flying to one anf from another airport cheaper, andd when later changing flights your checked-in luggage "follows" you - no need to check it in every time again