Ballito to Stanger is less of a problem I used to ride that section often. There is generally a wide shoulder. Mtunzini to Richards Bay really isn't great particularly as you'll get there later in the day. Perhaps call it a day at Mtunzini?
I've done the whole route but never all at once. Take M4 from Durban to Ballito and then R102 from Ballito to Richards Bay. The sections from Ballito to Stanger and Mtunzini to Richards Bay aren't great. Busy with people, taxis, broken glass etc.
I was in a bike shop the other day and a guy was buying a 60k Cannondale Evo through this crowd. He was going to pay 2k a month for three years. So interest rate was around10%. The bike shop was going to have to give them 10% but they were happy enough as it was a bike they wouldn't have sold anyway. Also the bike shop was not allowed to give discount under the rules of the scheme. Customer had to pay full RRP. I think it sounds like a really good deal to me and will definitely consider for future purchases whether I can afford cash or not.Where else can you get such cheap credit? Use your cash for something else.