On Forest River it seems the actual placement varies to what mood they are in. I have seen same model, same year in different locations. All are near the front, near the batteries... near is 6 feet or so.
Look on the black frame. Sometimes just the plug and weather cover over it. Black.
Sometimes mounted on side of frame right side.
FR wires theirs for ZAMP which uses reverse polarity. If you don't get a Damp, then you just get a polarity reversing plug or pigtail.
Before spending money on any solar, first determine what you expect to power and how long. No such thing as too much solar, but not enough and you'll be lucky go charge house batteries and run a laptop and a few DC lights.