The metal work is on its way to completion and most of the rusted carriage bolts have been removed from the frame using bolt cutters. When I inspected the J-rail more closely I discovered that interior leaking at the corners was a result of deteriorated butyl tape at the siding joints and incorrect caulking repairs. The trim was also missing along the bottom of the camper where the siding and the floor sheeting meets which could explain why the perimeter floor framing was rotted...
Otherwise I snagged a neat set of vintage Bargman exterior lights and hoarded some lumber/hardware/appliances.