we did used to do it
the burnt down holiday camp our trails were on was a big site with 3 tennis courts linked by 4ft drops , we even had a big hall
we would drag whatever we found lying around to create stuff , bath tubs were in abundance , as were concrete blocks . chalet roofs would be an effort to drag over and had a crappy transition
most memorable was the big jump box and the quater to sub box in the hall
shame the set ups would only ever last about a week before local lowlifes that used the place too wrecked them , we had nice 6ft boards of wood but they quickly got broken
we didnt utalise what we had to the fullest really