We have camped twice at Camping International Nube D'Argento just on the outskirts of Sorrento. However, access is very tight. Once off the main road, you have to negotiate a series of z-bends down a steep hill to get to the reception and the touring slots. (look on Google maps) I have a Santa Fe and a Fendt 7.03m caravan and both on the way in and out, I had very little margin on one of the bends (10 cms!!) but with a bit of toing and froing, we managed without having to unhitch. However, if you took it very slowly it might be possible. There were bigger permanent caravans than mine there. Having said that, I had nightmares for weeks before going back. Also the drive from the autostrada to Sorrento can be a bit hairy - rather like dodgems meets F1 meets 'wacky races'! If you get Parky or one of the other moderators to give you my email address, we could talk better offline. It is worth persevering - the whole area is stunning. If you don't manage to get in touch, I would caution driving the Amalfi coast. You will spend all your time avoiding hazards and traffic (breathing in on many occasions) while your passenger(s) will enjoy the stunning views. Much better to settle somewhere and take the bus.
Regards,
Bob