GREC 2013 is taking place at Lehigh University. Lehigh University, Bethlehem, PA is a 1h30 drive west from New York city, and a 1h30 drive north of Philadelphia, as shown on the map here.

The exact location of the conference room on campus is:

Lewis Lab 270
Sherman Fairchild Center
16 Memorial Walk East

(that is building 16 on this map)