Sorry about all of the work you have to go through. In regards to your wiring schematic do you need one for the Dodge Chassis or for the Motorhome, if you need one for the Motorhome we would need to have the Manufacture of the Motorhome that way someone may have it.
When I had a 77 Sunland on a Dodge Chassis I found that it was a simple (Basic) wiring system since it did not have any computer circuits to run the appliances as the newer coaches have. So at times it was easier to run a new wire rather then try and trace the old one.
For the Chassis if no one has it, you might try the Library they often have wiring diagrams for vehicles.
Wish you the best and welcome to RVing.