I'm not here to help but I'm gonna answer your question.
Charizard will be able to walk through walls when it gains the IQ Mobile Traveller through feeding him Gummi. Red Gummi will be more effective since it raises more. And you need alot of gummi, since the IQ is rather high that is needed for Mobile Traveller.
However, the disadvantage of walking through walls is that your belly decreases faster.