Gertrude Saddle is a steep, exposed alpine saddle in remote Fiordland, so treat it like a serious backcountry route rather than a walk. There is no marked track for most of the way, you will be route-finding over tussock, scree and rock with fast-changing weather and almost no cell coverage, so go only if you have good navigation skills, alpine experience and a full-day time budget. Carry a map, compass and GPS, waterproof layers, extra food and headlamp, and helmets or ropes if you plan to scramble; check the Department of Conservation for local advisories, tell someone your plan, and consider hiring a local guide if you are unsure.