Ponta Malangane is a fantastic place. Most importantly there is a bloody brilliant bar!!!
WRT your Scenic. Let's put it this way, if I was going up there I wouldn't take my Scenic, unless it is the 4x4 one. It is not that the roads are bad, it is more that there are no roads! There are paths through the thick sand that vehicles follow. I will send you some photos if you are interested in what it looks like. There is however another option. All the operators can provide a shuttle service to and from the Kosi Bay border post in their own 4x4 vehicles. Ponto Malangane I would guess is aroung 25km from the border, but the roads push the trip up to around 40 minutes. What you could do, is take the shuttle service, have a look at the roads on the way, and then decide whether you are willing to take your car on the roads. If so, you pay the R100 shuttle fee and collect your car.
I find it good fun taking an off road capable vehicle up there as there are plenty of places to go explore in the car. If you could maybe rent one from Durban for the days you are up there? Although renting a 4x4 for a trip to Ponto could get pricey.