There are MANY reports of people dragging everything from bikes to generators down the road by one bumper weld or a security cable because they tried mounting carriers to a standard square RV bumper ("bumper" is really a misnomer - they should just call them sewer hose carriers). Take, at a minimum, Don's advice and have a fabricator weld up something strong to the frame. I would also share others' concerns regarding the load and balance issues with such a small trailer.
On a personal note, I wouldn't want to be near you in a campground while you use a Champion 3100 to run your AC. I hope you are talking about private land or BLM/dispersed camping.
Rob