influenced by a few post ( here) and youtube video's I had a go at the area behind the garage ( not used to anything beside the trampoline for the kids anyway.
Nice track area. looks like lots of area to work with and just wetting down a bit or a lot would change the whole drive from dirt to mud with puddles. A few removable fake trees and buildings and bridges to switch around would allow you to customize the area pretty quickly into any type of terrain you feel like using.
Wish I had that much free space to do something similar.