She needs to offer a little more than 'rail in Auckland, tax the water bottlers and tax the farmers.' She seems to forget that most of NZ are run on farmers so she has just killed that segment.
Farmers generally vote National so she's not really lost anything there!
A little triangulation is a good idea, but there's a reason why Labour isn't throwing all its money into winning Clutha-Southland! Plus a price on water is a super popular policy.
Also tourism is now bigger than farming too. If farming is reliant on subsidised pollution clean up, free water and illegally cheap labour its not much of a profitable industry then is it? If it can meet its costs and not dump them on the rest of us and pay a fair wage for living in the wops and getting up at 4 in the morning in winter then, hey!