Pennsylvania weather is pretty bipolar, especially around this time of year. If it's indoors then it really depends on the temperature they keep the building at. I'd say a swimsuit or two of course, a pair of jeans or two, a pair of shorts, and a few shirt options like t-shirts, light sweatshirts, and heavier sweatshirts. Anything else like more semi-formal tops if you plan on going to dinner or pajamas are up to you. When packing for trips the most important thing is that you bring more bottoms than tops and make sure every top can be paired with every bottom for more options