On the way between the oppressive heat of the bushveld at Polokwane and the sweltering Lowveld around Tzaneen, you'll encounter the Great Escarpment, just as the Voortrekkers did nearly two centuries ago. Your trip is likely to be less bothersome, though.
On the other hand, they almost certainly got to spend more time exploring the huge forests of Magoebaskloof and Modjadjiskloof, unless you stop to walk the Magoebaskloof Trail, that is.
You can drive the two kloofs in a morning, if you want a glimpse of them, or you can stop over at places like the Modjadji Cycad Forest and Debengeni Falls, deep in the forest. You can camp at Ebenezer Dam, or treat yourself to a night in the old coaching inn, the Coach House Hotel. If you whizz by, you cannot really say you have been this way at all. And if you carry on towards Leydsdorp, you might find the fabled baobab with a pub inside.
The idea for this route came from a book by T.V. Bulpin. You follow the trail of the old ivory hunters, more or less in an arc around the top of the old Northern Transvaal (now Limpopo). It is the brainchild of the Limpopo tourism people.
The full trail is some 2000 km long. It starts at the southwestern tip of the Kruger National Park, goes west through the Strydpoort and Waterberg ranges and then heads along the Limpopo River. It briefly dips into Botswana's Northern Tuli Game Reserve, then more or less follows the Limpopo to Crook's Corner at the northeastern tip of the Kruger.
You can book any section, and accommodation is as varied as it is charming. If there is one adventure 4x4 trail you ever do, this should be it.