I dunno man, running away from home for half the country couse you are socially akward and didnt want to go to school?
That hardy seems a valid reason, tbh. I mean, if mc gets found out, he could very well be charged with kidnapping and go to jail, no questions asked, so that seems like a massive risk.
If we are getting a higehiro2, then i expect the reasons for the runaway to be life or death, or something equivalent to it, like an abusive stepfather/mother, some serious case of bullying, or something along those lines.
Being a hikki and having your parents mad at you doesnt seem like a strong enough reason for me.