Apollo 13 holds the record for farthest distance from Earth, because in its aborted mission, it swung farther around the moon at higher altitude rather than dropping into lunar orbit.
Apollo 13 holds the record for furthest men have been from the earth.
If we're looking for the furthest any inividual has been away from the nearest second human, we're looking at command module pilots. I think that record goes to Michael Collins, from memory.
Furthest from nearest humans on the earth's surface is probably unknowable; my bet would be on a liferaft somewhere in either the Pacific or Southern oceans about 100 years ago, and the poor individual concerned not making it.
Yes, the lunar orbit of the command module was not far about the lunar surface. That means that when the command module was in the part of its orbit that passed near the part of the Moon where the lander was, the pilot was not far from other people.
However, half an orbit later, he'd be all the way on the other side of the Moon from the nearest people. That's considerably more than a few hundred miles.
http://en.wikipedia.org/wiki/Apollo_13#Mission_notes