Rep Grinds are not as bad as they used to be in the past. The above posters are correct in their assessments, the best way to grind your rep with CE is to run the 5-mans in Coilfang until you get to honored, then work on quests, including the plant parts one (although I do not know if the plant parts give rep past honored). I do know that there is a repeatable quest involving the lvl 70 5-man raid in coilfang (forget the name) that DOES keep giving rep all the way to exalted. In any case, saving quests until after you get honored is a good idea.