We returned from Cavtat in June and bought a guide book and road map with the intention of hiring a car. After my husband looked at the map he decided that to get anywhere would take too long as there is only really one main road which runs all the way up to Split.
Cavtat we found to be quite small, it's very pretty but I imagined it, (going on the photo's I saw) that it would be larger than it was.
There's more information in our resort reports
HERE
If you haven't been before I'm sure you will love Croatia. It's very clean, no time share or restaurant touts and is very picturesque.