There 's no way to know which restaurant he will visit, but you should prep all the inspectors dishes for all restaurants. Even if he doesn't visit one this time, he might the next, and you will have that dish preped
Thank you so much. I also do not open the next restaurant until I finish the one I am playing. I will start saving gold and tickets to buy autochefs for every restaurant (except may be BBB and the Pizzaria because I finished them with 5 stars already). I think that since I don't have the chef arena yet it will be faster…