Will no doubt be very busy!!
Obviously you'd drive along the Amalfi coast - wouldn't want to do that in anything bigger than a Cali.
On our trip last year we stopped at Paestum. A bit further south but not much. Amazing ruins - two massive temples and a lot more.
Stopped at Camping Villaggio Dei Pini but I'd think you would have to book. The site was excellent, on the beach and an amazing restaurant. They seem to be open all year round. Only downside was the utterly mad proprietor who thought he could speak German and insisted on speaking German to everyone but no one let alone the Germans there could understand him.
On the main road is a pasta maker - delicious pasta, you just have to ring the bell if no one is there and an old dear comes along from a couple of houses away and shows you what they have.
The area just south of there is also great for walking although it will be very hot in August.
Marina de Camerota was nice although no campsite references there, they were all shut so we wild camped on the beachfront.
Further north lake Trasimeno is nice. Easy driving distance to a lot of touristy places.