Jadwin Gym @ Princeton University. The place might as well have been built for a FIRST regional.
The picture you see is taken from the stands. In the foreground is the basketball court (one or two playing field(s)). In the background is the track (think pit & practice field space), which you can't see because there is some sort of a reception going on in the picture. All the stands front the basketball court, and there are about 5000 seats in all (that's a very rough estimate, and probably a low one). Parking is usually plentiful in the lot behind Jadwin
Nobody is really using this place regularly after the basketball season ends. Add to that the fact that Princeton University wants to beef up their engineering program and late March is a great time/place to advertise to students...
Whenever the contract with Sovereign Bank Arena expires, FIRST and the organizers of the NJ regional ought to look into making a deal with the local Ivy League University.