I'd use buffalo board it's very high quality weather resistant ply with a tough, durable non slip coating on the front / back. I've used it the past for all kinds of applications including boarding out my old trailer bed and it lasted years sat in wind/rain/snow when not in use and being heavily abused when in use.
Foo, that is way different than the buffalo board I've always known, basically a lightly heat pressed fibreboard made from whatever garbage was hanging about that day after all the real composite materials had been manufactured.
I'd use buffalo board it's very high quality weather resistant ply with a tough, durable non slip coating on the front / back. I've used it the past for all kinds of applications including boarding out my old trailer bed and it lasted years sat in wind/rain/snow when not in use and being heavily abused when in use.