Quickest would be a Minne van, but probably the most expensive. A regular rideshare is a close second and less than the Minnie Van. THird option is to take the boat to the MK and switch to a bus to AKL. Same for return trip.
On the rideshares, this presumes you have a reservation when they check you at the gate. Less of an issue with Minnie Vans. AKL tends not to be as militant about this, but worth knowing.