It would seem like you need to check the strength of the rear bumper. Some are only designed to carry a max of 100#. Mine is pretty rugged and has good attachment points to the main frame. I have a spare tire mounted, so I had to put an extension on my hitch to get out beyond the spare and ladder. I moved my spare to the far left. I then mounted a receiver hitch on the bumper with the extender and a double bike carrier (Swagman, I believe). The extension gets the bike carrier out beyond the ladder and spare. I also bought one of the clamps to tighten up the joints so the hitch and bike carrier do not move at all. This set up works great for me. I'm not sure that I would recommend a four bike rack with this set up. It would place quite a torsional force on the bumper. Perhaps you could also mount two bikes in another location.