A lot of people say "a hard road to hoe" but what they mean is "a hard row to hoe" (i.e., a difficult task). "A hard road to hoe" almost seems acceptable, but it falls apart upon closer inspection.
A road handles a lot of foot traffic and takes a beating from bicycles and cars. No one but a lunatic would want to hoe a road.
The metaphorical row in hard row to hoe is a more or less straight line of growing plants. A farmer uses his hoe to cultivate the soil and keep it weed-free so the plants may thrive.
And yet hard road to hoe has its supporters. But those who defend it on the basis of "close enough" are doing a disservice not only to the language but to themselves. They should aim higher.