I have enough frustrations with building in the first place so I can only assume that cracking it all up would be ten times as lengthy and frustrating. I'm assuming that you have already figured this part out but...start with big cracks and keep making smaller ones until it looks "not like a cartoon". If it were me, because this would make me tear my hair out, I'd just cut a hole in the top and let it grow out from there. Looks nice and good luck, man.