In October, she completed preparations for operations in the Treasury Islands and Bougainville. She landed fighting men on Mono Island 27 October, including a construction team which installed a vital search radar in less than a week’s time. Following the American naval victory over Japanese forces in the Battle of Empress Augusta Bay during the darkness of 2 November, "McKean" steamed with a reinforcement convoy to Bougainville and on the 6th landed Marines near Cape Torokina, Empress Augusta Bay. She carried additional troops to Bougainville 11 November, thence returned to Guadalcanal for yet another troop run.