New to Jayco with our 2007 Feather213exp.The ventilation sucks and Jayco says they don't have schematics for anything older than 2009.Would like to add roof vent in dining area.Appears to be plywood and styrofoam sandwiched together.Roof is only about 2 inches thick.Used camera snake in wiring chases and found nothing.Anyone have any advice or diagrams?