I had attended the NYC PEPC and this is what I know:
The interview is first, but we did not wait too long for it. They first collected our 8500 and then we sat in a room for a quick briefing. Then they started calling names for the interviews and you sit in a large room with other interviews happening around you.
Afterwards you head to HR if they like you, where you will get your TOL. The rest of the day is spent doing med eval, security, etc.
I started at 9am and did not leave until 4. The day did go by pretty smoothly, but definitely try to book your flight home for after 5 or so. During the briefing they did ask at what time we were leaving to try to get the people with the earlier flights moving quicker. But don't just rely on them.
Hope this helps.
