There was only one episode where Alton Brown used his real kitchen.
Although Alton's sister and nephew were portrayed by actors, his real mother appeared in at least one show.
The largest set from the show was the beach from the Squid Pro Quo episode.
Alton Brown's daughter Zoey actually appeared in several episodes of the show
Vickie Eng (aka W) is a licensed chiropractor and Alton is one of her patients.