You're asking about the nuance. If there is one, I would say it's this:
In the first example, "where he started a small trucking business" could be view as incidental information. Surely he did many things after he emigrated to New York City. In this interpretation of the difference, the author could have picked one representative item to add some flavor.
Example two describes a sequence of two events, both critical to the story. "There he started a small trucking business" stands on its own as a separate sentence. In the narrative, it's the next action of importance he did after arriving in New York, clearly not simply incidental information.