Marge goes further or goes farther?

I think the latter is correct!

Actually, 'further' is more correct. In most cases 'farther' and 'further' are so synonymous that it really doesn't matter as far as meaning is concerned. Both mean ' of greater distance'.

I live further away from school that you do.
I can throw a ball farther than you can.

Only a pedantic grammarian would pull you up.

Maybe Turnoi or Amused would argue the point?