i've been riding for years but i ride 99% paved trails. last summer i thought i'd try a local off road trail. come to find out i'm no good at the off road trails. i can't balance worth a d*mn at slow speeds. i get scared when i come to a 6-12 inch drop followed by a down hill grade, if that makes any sense. if the trail is rocky i have a hard time riding around the larger rocks without wiping out. i'm thinking about building an obstacle course in my back yard so i can practice at home. that way if i wipe out i won't have far to go.

what are some obstacles i can build or some exercises i can do to help?