but which I did not think I should need on the last stage这句话

我这有个例句：
I hired a car the day after landing and bought a comprehensie book of maps,which I found most helpful on the cross country journey,but which I did not think Ishould need on the last stage.
这个句子的转折蛮有意思的：在登陆的同日我租了一辆汽车并购了一本详尽的地图册,我觉得它对越野旅行很有帮助,不过在旅行最后阶段我认为它未必有用.
因为不知道你句子的前面是什么,所以不好翻译,你可以看我的例句的最后一句,希望对你有用..