Front or rear?

This is learned behavior, so you could get trained to drive that bus much as a ship captain steers those large shipping vessels (from the rear) or steer as we normally train ourselves, from the front.  I do not think either is more difficult for someone with no experience at all.  Once you learn to assume a location of reference though, all your training will revolve around that location. 

Note that not all learned behavior relies on vision.  We feel the movement of the vehicle, and even hear sounds, and that is part of the feedback system.  If you change places in the vehicle, the feedback will differ, and you would have to retrain your automated response. You could definitely do it, and it would not be hard for most people, but it would still be needed.

I'll give you a real example: video games. Many, if not most, video games give the player a choice of view, whether through the "eyes" of the character, or from a viewpoint behind the character.  Many of the games I have played will force a rear-view perspective when riding a horse.  However, I usually take the first-person perspective in games (I look at the world as if through the eyes of the character).  The first few times that I played games where that third-person/rear-view perspective got forced when riding a horse ended up with me unable to control the character/horse very well.  Eventually, I learned how to deal with the effects caused by the different perspective.

I am certain that players who always assume a third-person perspective (view from behind the character) would have had no issue learning how to control a horse in a video game.  They would, instead, tend to have difficulty adjusting ot the first-person perspective.

You would suffer from motion sickness and disorientation if you were looking at what is happen in the FRONT of the bus while setting in the back.
Since what you SEE and what you FEEL would always be out of sync, this would always be a problem.

It might get some getting used to, sitting somewhere else in the bus. A lot of driving is the feel of the motion of the bus. Sub marine commanders have difficulty steering their boat by remote control because they lack the body feel of the motion. If the display quits while you are driving you are in deep stuff.
Better keep the window.

no                                                                       

My guess is that it would be easier to learn to drive that bus if the operator were centered over the front axle.  The reaction forces the operator feels while turning would be correlated more closely with the changes in bus motion.