I'm restarting one, and I've gone at it from the ground up. Started with just grooming, see what happens, then hand walking, then lunging, then ground driving. We've had issues at each point because of his past mistreatment, but he's coming along nicely. We're sort of stalled at ground driving, I'm not sure he was ever trained for it so we'll lunge with two lines and work back from there. After that he'll go on track with the other pony and ground drive in poles, then see if he can handle the cart. He definitely had some behavior issues, so with one who has just had time off it should be pretty fun to just work through and see how much she knows.