I would like to know areas to avoid in the city and how safe is the place. what kind of food

Hi, I do not think it is necessary to worry about the safety in BJ. It is very safe for that city and you can have all kinds of food in the city. You may need to avoid the remote areas at night.
It is safe to ask any one for directions, but if you are afraid of that you can ask the police along the road. They are very kind.
It is safe to go out at night. If you are travel with a group of people, it does not matter. If you travel on your own, it is not suggested to stay outside so late.