The cargo carrier or bike carrier or whatever carrier, is the easy part and only as good as what it is attached to. My SIL found out the hard way about mounting a bike rack and bikes to the rear bumper. No bueno for $h!t.
I just looked up welding fabricators in Montrose. There's several. Call around and get a receiver hitch done right so it will last and you won't have to worry about what you attach to it.