Hi there my fiancee and myself went down to Sodwana for the holiday, we too went via Swaziland, entering at Mahamba and leaving at Golela Border posts, the road was in a good condition and there was hardly any trafic either specially large trucks and anoying taxis, the areas around and near the villages of DWALENI, MHLOSHENI and HLUTI had some pedestrian trafic alongside the road especialy during school breaks, it took us under a hour and a half to get to Golela from Mahamba and we would have been through in a flash there, if it was not for a Putco Bus that stopped 10 minutes before discharching a large group of people who were going through customs into SA.
The return trip was a matter of in and out of Swazi in a hour and a half, totaly worth the 50 eLangeni road tax (R50) one has to pay. Keep the receipt for when a trafic officer stops you (not likely)otherwise you have to go through a longer system to obtain the roadtax certificate aka a fine
The road is in a beter condition than most SA roads and not 1 pothole was encountered from the Nhlangano turnoff to Golela
It would be a breeze dragging a boat across this section of road even with a 4x2 vehicle. The uphils are moderate and there is only one section with a steepish uphill that would require gearing down to a lower gear ratio.
This is definitly the way to go until the Piet Retief Pongola Roads have been completed
Good Luck