EVen though my 27 MB LT has the swivel feature, I still trailer it the old way. GD's manual recommended a rope tieing down the handle, the rope stretching across the gunwales just like your regular boat strap. I use two bungees to a couple of metal clamps that are screwed into the rear pods; I also use another two bungees on the handle and these have clip ends that are positioned in a gap between the welded in rear floor and supporting ribs. The "failsafe" is the boat strap.
I also have a bright red flag on the prop assy. and reflective tape on the rear of the boat guides. Some guys add a removable clip light to the prop assy. I just drive extra careful and use my emergency lights when vehicles approach from behind in the early morning hours.