Some kind of tiller to break up the dirt/clay makes it easier to move and shape all the new jumps and keep the racing surface exactly as you designed it. I used to rent one that attached to the bobcat, others have one that attaches to the back of a tractor. Speaking of designing layouts, drafting paper with the squares on it helps keep things to scale. Have some reference points around the track that you include on the paper. Its a lot easier and faster to change stuff with an eraser than a bobcat and having an exact diagram to follow saves several hours (and sore backs).