Welcome, Tom! Another Arizonan here, White Mountain area (Pinetop).
As I’m understanding your question, you’re planning to carry some bulky items on the floor, no? I’m guessing they’re things you will unload when you get to camp and use outside? We often carry a large ice chest, some camp chairs, a portable awning
, a bin of set-up stuff (chocks and leveling blocks), and a small portable bbq. They ride fine sitting on the floor. Ours has carpet, but if you have vinyl and are concerned about sliding around or scuffing, put down a rubber-backed throw rug or use pieces of gripper pad. Things that are unstable or have sharp edges should go in a bin or box. First time, stop and check after a few miles and see how they’re doing. Common sense, really.
As the others have suggested, it takes more work to keep stuff inside the cabinets from getting scrambled. I lined all the cabinets with gripper pad and gather small items into bins. The higher in the trailer and closer to the back, the more movement. Stick with lightweight stuff there. Heavy stuff low and centered. It took a few trips to get it all figured out.