I spent some time last June in Sicily and found it wonderful. If you're interested there's a travelogue on Zine Files section. If the ferry takes you to Porto Empedocle, near Agrigento, you can enjoy both the ruins and the coast. If it goes to Trapani, the surroundings of Marsala and the northern coast are also nice. I'm not a camper, but I noticed many campsites along the sea or inside agriturismos. Have a nice trip

Paolo Trieste, Italy missing the sweet sicilian cassata