You could have a small door on the front vertical section that opens out like an ashtray. It would be hinged on the bottom and open to 90 degrees. On the back of the door would be a 45 degree steering wheel mount. You then would need to construct a removable steering wheel similar to what they have in NASCAR. The hinges would need to be extra strong and you might have to add 2 locking struts to keep the assembly steady. For the pedals you could make a drawer like 1UP does in his new cab. You could also store the steering wheel in the drawer when not in use. You could also just mount the pedals to base.