I took a day trip out to the Egadi Islands from Trapani. I don't remember which one(s) I saw. I was underwhelmed as an American who doesn't go to Europe to sit on a beach, even an uncrowded one. I now understand that any uncrowded beach in Europe is going to get great reviews even if there isn't much else nearby.
For your purposes, it sounds as if this could be a worthwhile jaunt. However, as of 2015 it was important to buy your ferry tickets in advance, because visitor numbers were limited (that's why the beaches are uncrowded). In addition, you had to choose the time of your return boat when you bought the round-trip ticket. There were two companies making the trip, and you had to travel both ways with the same company.