Dean wanted to get a fair distance between them and the city before somebody recognized Julip. It wasn't only for his own selfish reasons, but also because nobody would know how to handle a werewolf, nobody would know what she was, without wanting to kill her.
Dean didn't have a goal to set for, so instead he let Julip point to a place on a road map. His plan was to get a job, find an apartment or house, and then figure out the rest. He needed to erase all trace off them, his dad didn't need him so he didn't need to feel any guilt about leaving him behind. He did not think he could give up hunting completely, but he could take a break for a while.
He called his father and left a voicemail explaining that he had to go, and that he didn't think he would come back. take care off your self old man, please don't look for me Julip hugged him, and gave him the strength to say his goodbye.
