We first visited Croatia about 10 years ago, when we had a few days land based, a week sailing through Moorings, then another 4/5 days ashore. I don’t know if they have changed the base, it was north of Split. Sailing distances were fairly long with few places to provision en route, so it might be one area where I would consider a provisioning package. It was virtually a days sail to get out of the inlet where the base was sited and having only one week we literally went north for the next three days, then turned round to come back. We were there in late September and experienced all seasons on several days. Including snow!
That said we love Croatia and returned to go on a small cruise boat three years ago. Again,loved it. The country had seen massive changes in that period: more tourism, much of the war damage covered or removed, the local people speaking more English -on the first trip German was more widely spoken than English but they had then realized that English was more used world wide and so more influence on teaching English. So, beautiful country and people. May be longish sails each day. Sorry not to be more specific as to actual sailing destinations. Have a wonderful time.