== Maybe, but Reckless == 

 Perhaps he did not make any mistakes, but certainly he was reckless. He went into an unknown (to him) wilderness region without a map, something which would have very likely saved his life. Now he may have done that willingly and therefore it was not a 'mistake' or oversight, but certainly something unwise to do. Even the frontier explorers would get what assistance, both gerographical and material, from the local peoples when ever possible because of the extreme risk of entering the wilderness blind and without aid. McCandless may been a capable outsdoorsman seaching for something spiritual, but entering the wilds without a map was extremely risky behaviour.