Yes "The Power of One" can be used as related material.
I'm actually reading it at the moment, so im not really sure how it relates.
I guess the boarding school and the train trip mainly as they contribute to inner journey. Boarding school makes him physically stronger from the torture he had to deal with, as well as more mature as he was surrounded by much older children and did the judge's homework etc. Hoppie contributes by teaching him about boxing and life, there's that bit where it says if you fight with your head and then with your heart, small can beat big.........or something along those lines. he also talks about the power of one in that bit.
Oh and there's also the imaginary journey, where inkosi-inkosikazi cures his 'night water' and he imagines himself at the waterfall
