Wathumba creek would be ideal for this..
We used to take everything up via boat, but you could have a car meet you on the eastern side of Wathumba with supplies I guess..
The best anchorage (deep channel) and camp ground is on the western side though (opposite there)..
I guess the only downside would be access to and from the creek at certain stages of the tide, cant help you with that unfortunately as it has been years since I have been up there!
Maybe someone else could chime in with that info for you if they have done this trip recently..