One of the highlist for travellers in Africa is the journey from Cape to Cairo. many have done it and many have written a book about it. Grocan must have been one of the first to do travel in this way.
But there are others possibilities, cross the continent from east to west, or from west to east. The South African traveller Johan Badenhorst started his journey in Lamu, the famous island of the Kenyan Coast. And, yes, he wrote a book about it.