As soon as the game prompted me to meet Nemona at school I left mesagoza and haven't been back. I've been completing the dex on foot. I'm limited to poke balls at the mart, whatever I find on the ground, and the dex milestone rewards. It's been difficult but fun. I'm at around 230/400. My goal is to unlock all of the teleport points and then I'll probably go back. Has anyone else been doing this?