Croatia is an amazing place! I have been there several times and I definitely suggest your guys to go to Premantura (early in the morning to get the best spots) as it's an amazing natural park, with astonishing coast where swimming feels like paradise. There is a typical restaurant (just one) in the middle of it, where you can eat local meat (pork manily) that's very nice.
I also suggest the Krk Natural park where there are very nice and big waterfalls with nice walks into the deep nature.
Have a safe trip there and enjoy your Family time!
Will see what we can do. There is a water taxi to Dubrovnik from where we are that we will try. Not sure how much we will "travel" on this trip with Smallsteps though - she is struggling a little in the heat - totally not used to +30.
Thanks for the tips!