The whole thing could be done with potentiometers. Multiturn pots at each end. What you would be making is just a bigger version of something similar to a standard hobby servo. Basically - at the steering wheel end you would be "creating" a refernce voltage that you would then compare to the voltage present at the gearbox end. and then itf the voltage is higher or lowere you use that to decide the direction and speed to turn the motor on the gearbox. The difference between the 2 is referred to as the "error voltage" This can be done with linear circuits or Analog to Digital circuits.
Using a couple of potentiometers is probably going to be much simpler than using encoders, as absolute encoders would be needed and they get expensive. A good multiturn pot would give good, repeatable feed back.