If source has a grounded neutral, then during a ground fault the fault current ultimately returns to the neutral point of the source, but in properly installed setup, that neutral point is only bonded once and is bonded at source or at first disconnecting means, so any neutral conductor beyond that bonding point isn't going to see the fault current. So for properly installed setup ground fault current follows equipment grounding conductors, metal frames of bonded equipment, etc. until it reaches the bonding point, from there it follows the grounded conductor the rest of the way to the source, but should be a short distance from the source.
Of course utility power and MGN distribution can allow for faults when on utility supply to follow other unintended paths at times, but we are usually arranging things so that the EGC path back to the bonding point is usually the lowest path of resistance and the bulk of fault current will flow to that point then back to source on the grounded service conductor.
