My wife and I and 2 friends are holidaying to Czech Republic/Slovenia/Croatia in July/August this year - we are cycling for 5 days from Prague to Vienna, training to Ljubljana and spending 5 nights there (day tripping every day as we have a rental car and yes we will be dropping it Zagreb and am happy to pay the drop off fee).
Our friends then leave so my wife and I have 9 days on our own - we want to spend that time in Croatia and have decided on the following (bare in mind that I realise we might be trying to see too much but if we can get a taste we will come back again)
Drive from Ljubljana to Rovinj
2 nights in Rovinj (explore Istria - Porec, Groznjan, Motovun, Vrgar etc)
1 night at Plitvace Lakes (get there late afternoon and start early the next day) then drive to ......
Here is where I need help - we need to drive back to Zagreb to fly home and I think we will do that drive the day before we fly so that leaves us 4 nights. I think we would like 2 nights on an island to relax a bit (keeping in mind we will still have the car) so any recommendations on what island to choose would be much appreciated (not into partying but love walking, scenery, history etc)
The other 2 nights we want to spend on the mainland in the one place where we can do some day trips (would love to see Mostar) and then drive from there to Zagreb. Any ideas would be great - I think I have decided against Split (and I don't think we can reach Dubrovnik) but am happy to receive any advice. Sorry for the rambling question!