Between chalets 3 and 4 in Injisuthi Camp you'll see a rock marked Van Heyningen's Pass. It points you towards the Delumhlwazini River and over a wooden bridge. Follow the path next to the stream and 500 m further you cut through the corner of a pine and bluegum plantation.
Just 80 m beyond the plantation the path swings to the right and climbs 15 m up a hill (be careful here: if you carry on straight, you'll end at the Old Hut.) Turn right at the T-junction to Van Heyningen's Pass, as the sign says. After a few hundred metres you'll enter a forest with streams. At the top of the pass, you'll find two lookouts.
Take the same route back.