Apologies for kind of butting in here as I am not going on this trip! I have been twice to Rabac in the past, (mid 80's though) and had a great time. It's a lovely village with some stunning scenery and the people are so welcoming.
Do NOT under any circumstances miss the Plitvice trip! But make sure you are wearing very sensible shoes! And the caves and Stud Farm are lovely too. I went to them when I stayed twice in Slovenia. Incidentally Olly, why don't Just You do Slovenia? It would be a great destination for a walking holiday and the Lakes are so nice.
Mick I would say that the transfer time is easily correct. I have only flown in Pula when I have visited Rabac, but the transfer time from there was well over a hour to Rabac.
Have a great time those that are going.