Game park near Johannsburg

[Zululand]

I have a query:

My client is working for 1 week in Joburg in January 2010 { 17th-- 22nd } and then would like to relax for 1 week in a Game Park where she could do Game safaris, maybe horse back safaris and have 1 to 2 days to herself just to relax.
She would like to be picked up from her hotel on Sat. morning the 23rd of January and taken to the park and then brought back to the Airport in Joburg on Saturday the 30th January.
Can anyone suggest the best Game Park to go to bearing in mind the above criteria?

Have a wonderful Christmas,

Robert