Such a shame we live in sheep country! I could prolly borrow some off a neighbour!!!Tunnels maybe aren't so good in a hot climate, the sun will also perish the plastic quicker than at higher latitudes.
Concrete, I was never that struck on, it is pretty expensive to lay, slippery when wet, and if water does blow in in a storm, it doesn't soak away so quickly on concrete as on bare earth.
The old Cornish way was to ram the earth floor, and then smear it with cow dung, which polished up quite well.
If you have cattle, they will do this for you quite naturally.
If you don't, a whacker plate does quite a good job, and they aren't expensive to hire for a few days.
Our drive in the UK is scalpings rolled and whacked with a proper machine. Then big gravel on the top. It does a good job and keeps the weeds down but to work on it I have to use things to lie on and roll jacks around on. I tend to use hardboard or old kitchen worktop, which is good and tough.