Work out the current and voltage assuming 25 Ohms of resistance for ground rod, 1000 ohms of resistance from hand to foot. And the conductor resistance of 14 AWG copper.
I would bet the current and voltage would be so insignificant that it wouldn't be a concern at all
Well good point we need to put some numbers on this scenario say its a space heater in a barn.
First the load, say its 1440 Watts, that the max load you typically see on a 120V circuit, that would be a 10 ohm resistive load, like a space heater.
Now we need a circuit length; say its 490 feet out to the barn.
Now we'll use the numbers others have said, 25 ohms for the grounding system, and 1000 ohms across the person.
Now its just a matter of solving for the combination circuit.
EDIT Hold on never mind, he said the neutral, this is for the hot