New.Flatbed. What should I be concerned/thinking about.

Try to insure that the tires don't rub on the bed when the weight comes on the bed, especially on cornering or rough roads.

Utilized the area under the camper skirts for storage if you can handle more weight. Just a small side board will work on both sides for rough items.

A thin rubber mat might help stabilize the camper, it shouldn't go anywhere with 4 tie downs anyway.Dozens of flatbeds on the road with only a few straps and chains on the cargo...