I'm a newbie and only have a 26 footer but I have to park alone and use the driver confidence method mentioned earlier - Backing Into a Campsite. I got 2 orange pop-up cones from Walmart. They "pop-in" to small flat packages that sit on my passenger seat. I get out and walk the site to choose the best placement then place one cone at the center back position that I want. It will be visible in my rear view camera when it's time to stop. And the other cone I place at the front side position where the other person would stand in the "backing into a campsite" procedure. I view it in the side view mirror and wait for it to start to disappear as I am making the prep turn. This took parking lot practice.
This is another link describing the same process that you can print out for reference.
Link