This will be an assignment that has to be driven by your own sensibilities and perceptions of the short story and the characters within it.  There is much to go from given the richness of Gordimer's text and the underlying analysis within it.  I think that part of the diary entry would be well set to discuss from where to where the narrator has come.  Discussion of what the trek must have been like through Kruger Park and engaging in some type of reflection would make sense.  Now that she lives in the refugee camp and the trek is over, I would this that she would think about it and engage in some type of formative understanding about what she endured.  At the same time, I think a part of her diary entry would be connecting her experience to others.  She lives in the camp and would be seeing more people like herself enter and perhaps her entries could spend some time seeing how she has changed from this point and how these other refugees' experiences are similar to her own.  Given the fact that she is in school, it would make sense that her scope of perception is widened and her entry could reflect this.  Finally, I think that some level of sadness has to be felt because while the majority of her family is together, there are some notable exceptions, such as her mother, father, and grandfather not present, so the diary entry might want to encompass some of these conditions, as well.  There is a joy for being together, but a certain melancholy that not the entire family is with one another.