After talking to Gus, he told me that the reason he used wheels and not a joystick was this quote.

"I originally planned to limit the travel to a specific range and to use
levers but I found that there were limitations in the LEGO firmware that
prevented me from doing so. It seems the LEGO firmware also detects that
the motors are in a stall position when trying to get back to a certain
target position and then it seems to move the current encoder base position.
When it does that and I attempt to straighten the lever, the lever is now
actually a few degrees off. That is why I went with the wheel inputs
instead of the levers to get around that problem since it is not problem if
the wheel does not return to the exact same position."

                       Typed by the fingers of Gus.



So, I decided to take the wheel approach, and have one wheel, (the steering wheel), sideways, and the drive wheel vertical, to make it seem like a steering wheel. The motors will be very simple to attach.