Wit Els is the king of the Cape kloofs: the ultimate 3- to 5-day kloofing experience.
The trip begins with a tough ascent of Waaihoek in the Hex River mountains, and a descent into the river, which will take most of a day to complete. The ascent has some charming names like Hagga's Hill, Little Agony and Big Agony. Because of the heat, the ascent is often done at night.
In the course of the river there are more than a dozen "compulsory swims" and many kilometres of the best kloofing in the Cape. Landmarks include Barrier Falls, Emerald Pool, Boulder Pool, the Supertube, and Bumslide Rock. There are many beautiful camping spots beside the river. The waterfall in the picture is called Disa Falls, it's huge, freezing, and the best thing in the world after the 900m ascent and descent into the kloof.
Since you'll be swimming and carrying a full pack, you'll have to do some serious waterproofing, and think about carrying a lilo.
The landowner once asked me not to include their contact information on a page about this kloof, so you'll have to track them down yourself. I'm fine with that. Frankly, it's a very tough hike putting parties very much at the mercy of the landscape and the elements, and I don't want to take the blame for the next kloofing accident.