Depends on the trailer though. I have a little 4x8 tilt trailer I use for my snowmobile, that is the most miserable thing to back I've ever seen. Goes where it wants, and jack-knifes easily. Also have a 5x10 that goes right where I want it every time. No idea why the difference, fortunately, the small one is light enough to maneuver by hand.
Was commenting about it once to my BIL, who used to be a truck driver. He said small trailers can be some of the hardest to back.
Never did a fender, but I did munge the tailgate on my truck on the trailer jack. Had the tailgate down so I could see better, and there was enough clearance for slight turns, but not a sharp one. Lesson learned hard way...remove tailgate before backing with trailer!