Does anyone know if booking on a campsite for a year would count as Proof of residency or booking a property on AirBnB, booking.com or similar?
People on the “Americans in PT” Facebook group seem to have managed it with an Airbnb booking. YMMV and there may be process things included.
It depends on your Embassy. We managed to be approved on a 6 month refundable lease on Flatio.