Complex sentence: When printing jobs needed to be done, the people of Perth Amboy went to New York City, while the people of Burlington went to Philadelphia, since that city was more convenient for them to get the printing work done.
Split into simpler sentences: When printing jobs needed to be done, the people of Perth Amboy went to New York City to have it done. The people of Burlington went to Philadelphia, since that city was more convenient for them to get the printing work done.