Basics to camp your way home include wheel chocks, leveling blocks, round bubble level, water hose, pressure regulator, extension cord, 30A to 15A adaptor, sewer hose, black tank treatment, jack (tow vehicle jack may or may not work), lug wrench, tire pressure gauge, lighter, basic tool kit.
Many manufacturers offer a starter kit as an option, which includes some of the items on the list, probably not all. Most prefer to purchase their own so they can choose specific products and brands. With a new molded fiberglass
trailer, it passes the time while you're waiting for it to be built!
I really wouldn't stress over it too much. Walmart is never far away and typically carries many of the items you need. There's very little you can't manage without for one night in any case.