All make perfect sense. "Up to" is a bit more descriptive than "to". "Up to" says that he came close to you. "To" doesn't say that explicitly, but since he started talking it implies that he did come close. The third describes two events, one following the other. First, the stranger came towards him. Then, the stranger asked him the way to the station. You could insert "then" into the sentence to make this progression clearer but you don't need to because it is obvious. Similarly, you could say: "Billy enrolled in the high school and made straight A's." Clearly, some time must pass between enrolling and making straight A's, but you do not need to insert "then" because it is so obvious.

The third one doesn’t really make sense, if they’re coming towards you, they’re not up to you yet. First two are basically identical