Leaving the HQ, go east on I-20 to Exit 11, which is the Bovina (might not be spelled right, but I'll check my atlas when I come back in from the cocktail party--just giving you info in the meantime) exit. This is about six miles down the interstate. Go right off the exit and in 300 yards turn right again. From there follow the well-marked route which will be signed.
Distance from HQ is estimated at about fifteen minutes. The test will be just inside the gates.