We did this a few years back from a marina just north of Trogir. We had a great time, but one week was not really enough for us. It took a full day to exit the estuary in which we started, and thus had to allow for this at the end of charter too. We decided to sail north as we had already spent a little time further south. Not sure this was actually a sensible option. It turned into being long, daily sails and being very, very aware that we had to be back at a specific time. I clearly recall pulling into a marina one night to be met by Americas Cup teams who announced that no way would they have sailed that day! We felt we had no alternative other than sailing overnight in less than ideal circumstances,
Having said this, we thoroughly enjoyed Croatia. It is a stunning country with beautiful scenery and fascinating history and I truly want to return.
Do not over plan and do not expect to travel too far would be my advice. I can't remember mooring fees, so therefore I don't think they were very much. We travelled in September and often experienced weather of four seasons in a day, so be prepared. We adored Trogir and spent a few days there at the end of charter. Gorgeous. All in all, I would do it again, but do not expect to go to far (or go to the islands to the south). This was about 6/8 years ago and provisioning was not the easiest, but plenty of opportunities to eat ashore most nights, Hope this helps. I dont want to put you off, just being realistic and telling of our experience.