Hi Ronjde,
Don't worry because from the 1st of September is much much quieter here. I'm from Sorrento and August is really busy, from Castellammare to
Capri it's like an Highway.
From September you will enjoy the area, Procida is very nice, Ischia too and you will find a berth in Casamicciola, Capri I do not suggest to enter in the Port and stay outside Marina Piccola, Positano has no Harbour and Amalfi I suggest as Capri. If you can I will really suggest to go to Palinuro and Camerota 60 miles from Capri, one of the best places in the Mediterraneo.
Ciao and feel free to ask,
Maurizio