Hi,
I was positively surprised by Swaziland. In the Milwane you can cycle with plenty of wildlife.
But it's not Malaria free but rare. South Africa is partly malaria free but wildlife is nearly not possible to see from a bicycle. I only know the Buntebock NP, a NP near Graaf Reinert which can be cycled.
Wildlife, malaria free and cycling does not fit good together...
Thomas