We toured Croatia (three family's, two ribs) three years ago, island hopping 5 to 15 miles per day. We stayed on a different island every night apart from Vis where we stayed two nights. Even if you don't do long distances the boating really is endless. Trogir is a good place to base yourselves but the large island of Hvar would be fun too - imagine Dartmouth but with sunshine, not much tide, super yachts on the quayside and lots to do, cheap eating and that alone will give you plenty to play with. Do watch out for the wind in the afternoons, it can get a little gusty. Self catered accommodation with air con is available quite cheaply in a lot of places.