We have driven by car from Cape Town to Durban along the Garden Route. The roads are excellent. Take your time as the scenery is amazing and you should plan to spend time in each town - specially Knysna. If you love wine, there are many vinyards to visit and taste I do not know where you would park a motor home, but you should always be careful of your safety. Why not go by car and stay in the excellent and reasonably priced B & Bs along the coast before heading up to Johannesburg? There is a great book called Portfolio Bed & Breakfast Collection which we have sent to us each year free of charge. They can be contacted on info@africacollection.com. The book contains excellent maps and information.

You will have a wonderful trip. You should include a few days safari in Krugar

If I can be of further help, please let me know