Needed: Ideas for a cheap temporary Floor work surface

I've done my share of working in the dirt. I'v I think my stands might sink due to soft ground, a lot of rain, extended period, I'll put a short piece of 2X12 treated lumber under them. A piece of hard vinyl 42 inches wide that was above ground swimming pool wall is a nice temporary surface to lay on. If I'm going to need the trans adapter on the floor jack I'll first need to use the taller non adjustable tripod stands that once were scafolding stands. Those now have 5 inch clips of 5 inch channel iron welded on tops. Then I'll need the 4 foot by 4 foot piece of 1/4 inch steel tread plate to roll the floor jack on. This diamond pattern tread plate controls the roll of the floor jack very well.
I've done most anything I wanted with these few materials.