I live in Pennsylvania too. Philadelphia and I think Pittsburg have trans protection in the workplace. They can still fire me for low productivity or "we are doing something different starting next month". I work in Philadelphia. My employer has a LGBT policy and we treat 250 trans children in our Sexuality and Gender department. Diversity is in all 5 of the core pillars for the company. I have had no issues at work whatsoever.
I would make sure the prospective company has a LGBT policy. I recommend sharing with HR. I work with HR as part of my job. I made friends in HR and it helped me immensely. I shared my intentions, frailties' and needs. They helped me with my supervisor who put up road blocks for me to come out. I literally drove in front of a fast moving tractor-trailer on 76 because I was so frustrated and needed to come out. HR, my boss and I meet after the incident and I forced the issue about coming out. I had gantt charts with procedures, dated and costs. I also had my previous 3 years history on the chart. When the meeting was over HR went to legal and firmed the "deal". That day my boss e-mailed the CEO now COO (head of diversity) the situation and future events to unfold.
I have worked with the company 26 years and I do not kid myself, the moment I become a liability I am out. I worked hard to develop relationships, credibility and value. I am well liked as a male or female.