OK, since I'm from there so I can help:
So you are on Rt. 140 North. Make a left on Center St. Make a right on Gist Rd (after Carroll County General Hospital). Make a right on Smith Ave. Smith Ave dead-ends at the Ag Center.
(address is 700 Agricultural Center , Westminster, MD 21157 if you are coming from elsewhere and want to use Mapquest.)
It will be interesting trying to spot THR folks. I'm sorry I was unable to make the recent shoot!
I've never heard of "Buckbait" either. I did a Google on "Gun show Carroll County Agricultural Center September 13 14" and that's what I got....maybe they just have a display and aren't the sponsor, if so, sorry....