A method for detaching or installing a rotor blade from or to a hub of a wind turbine includes positioning the rotor blade toward a ground location between a three o'clock position and a nine o'clock position. The method also includes mounting a mechanical arm to an uptower location of the wind turbine. Further, the mechanical arm includes a torqueing tool at a distal end thereof. Thus, the method also includes removing or installing, via the torqueing tool, each of the plurality of hub fasteners so as to detach or attach the rotor blade from or to the hub.