what are some miscalculations mcCandless seemed to make

Chris made more than a few mistakes, each of which led to his untimely death. When he was dropped off by the truck driver, he forgot the map he'd brought along (or did he?). The truck driver also tells us that Chris didn't have the necessary clothing, nor was he carrying enough supplies. Although he did have a book on plant life, it is believed that Chris injested poisonous berries which caused him to dehydrate..... the river rose, something he did not anticipate, and without a map he never knew how close he was to a safe passage across it.