Sawzall or Blue Tip Wrench time..... Sorta kidding.
For safety reasons, you do not want a one piece shaft from the box to your chest as it becomes a harpoon in the case of an accident. Remember you can't possibly accelerate as quickly as you can stop - like, if you were to rear end a parked cement mixer at forty miles an hour. The last thing to go through your mind will be your butt.
Cut the cover off about 3 to 4 inches from the box. Cut the shaft about 5 to 6 inches from the box.
You must think in terms of a collapsible column or a coupe of u-joints and short shafts together with a sacrificial column. PVC pipe sounds dumb and can shatter to produce sharp edges and pointed ends that would be dangerous, but you get the idea. Supports for the column should be designed to crunch or fold and not be spears that could peirce you and that includes piercing an inner thigh where blood loss might be a survivability factor. That means no small diameter steel tubing or angle iron and nothing that you could impaled upon.
Check out woodwardsteering.com where I got my stuff for u-joints and a good primer on columns. They have a niffty engine bay collasible steering section that might be a good choice together witt a couple of u-joints and short shaft to the steering wheel.