Jenna wrote "...but it would be interesting to know the particular catalyst for settlement in Reading for many who seemed to have come from the same region in Slovakia."
You are right, it does make things all the more interesting. Sometimes the answer can be found in the church records. For example, in researching the church records for Jelsava I discovered that the town was full of leather workers, especially my ancestors. Some made boots, others processed hard and soft leather, some were tanners or skinners. Those that came here came to Pittsburgh. I wondered the same thing - why Pittsburgh? Then I started to research life in Pittsburgh at the turn of the last century. I discovered that there was a thriving leather industry here. Most people think of Pittsburgh and steel, but it also had the largest leather processing industry in the country. As a result they came here and apparently got jobs in tanning and leather processing. One of my aunts worked for (who I believe to be the grandson of) the man who started the leather industry here. Networking across the big pond.