Is it permissible for me to use the remaining money from tuition expenses, which my traveling father left for me, to cover transportation costs and photocopying instead of informing my father, knowing that my mother encourages me to do so, and I fear that this might be unlawful (haram)?

We ask Allah Almighty to increase your eagerness for goodness and for earning lawful sustenance. Regarding what you asked about, it appears that this money is usually tolerated, so there is no harm in benefiting from it in other permissible ways, especially if it serves your studies, unless you know your father dislikes you taking the excess. In that case, it must be returned to him.