The only advantage I can see to using the Walk path as you described is that you can see it laying on the ground.  Since the path is really nothing more than a spline curve it is easy enough to create a starting and ending point on the timeline and just put in extra keys to make it move left or right.  The walk designer has the flaw that it does not shorten/lengthen a step as it goes around a bend.  Trying to figure the math to make wheels turn at the correct speed would be very difficult.  It is possible (I did it when making the 60 second commercial), but that was knowing the size of the wheel and how far it was going to move, and even then, it probably was not correct.  However, it would be hard to prove it was wrong.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13