Some established campgrounds have policies on whether you can bring a dog or not. And if they do allow dogs, it's often a rule that the dogs must be leashed at all times. Because of this, always check ahead before departing to make sure! You can also disperse camp like we do. However, you should still research ahead of time to make sure the environment isn't too fragile where a dog could cause issues.
I always bring at least one extra meal and keep extras in my truck just in case! I also suggest doing this with water by keeping a gallon jug in the car at all times (that's a good thing to do regardless!).