Elandspad is an easy day hike close to the Du Toits Kloof tunnel. The path follows the valley above the river, and after an hour or two you rejoin the river at a very welcome pool at Fisherman's Cave. The river just above the cave is quite easy to explore, with a bit of wading, and some nice landmarks like the "Gog and Magog" rocks overlooking the river. You'll probably see some disas on the cliffs in summer. A steep tributary to the right goes off into a very spectacular narrow gorge ending in a very high waterfall which few people ever visit.
In the main kloof, there are some wonderful pools, waterslides and one or two optional jumps. Remember that you can't go too far past Fishermans Cave, as you will reach private property, and your permit doesn't allow you to go this far.
On your way down, you can actually follow the river all the way back to the road. the lower reaches are quite mellow and calm, and make for pleasant wading, although this annoys the trout-fishermen who share the lower parts of the river with you. Since the bottom part of the kloof is quite accessible from the road, there are often crowds of day-trippers in this area, who (unlike you) didn't pay for a permit to be in this area. Grrr.