Most roads are fine, even gravel roads, though if you ask a South African he will say you must have a bakkie (4x4 pickup van) if you go off the tarred roads

You will not have trouble finding wine farms all around, same for foods/restaurants, it's really hard to find anything but good food in South Africa.

Unless there is something specific you would like to see that warrants more than 2 night stay, you could do an even split of nights between all places.

Some of the places are pretty close by to each other (~2 hours drive or less), so you might want to sleep in one place and drive to the other during the day, I know I would prefer not having to move every night if I don't have to.