If there is no hell, then you don't need to prepare for it; if there is a hell, and you know that you will go to hell after you die, then you need to prepare for "not going to hell". If one realizes the illusory nature of the universe, and is able to see the nature of the mind and know the truth of the vacuum of the universe, then he has already left the six paths of rebirth and entered the four holy realms of the Dharma, i.e., he has become an Arhat, a Pure Blessed Buddha, a Bodhisattva, and a Buddha.
The six paths and the ten realms of the Dharma are all realized by the mind, so if you know this, you will not go to hell.