Well, I went today in search of a filming location near Senoia, Ga and I found it! Unfortunately, the police has it blocked off and there's no vantage point in which to observe filming. It's on a side road very near the studio.
However, I did snap some video of a couple of places in Senoia where they are storing the Woodbury major set pieces and of the location.
The video of the location was very short, but I made two passes and screen grabbed 6 stills from the video to post on my Youtube channel "ThePhoenix6430" to use in my "Deadite Joe Show".
Here's a couple of screen grabs so you can see how well protected the filming has become compared to Season 3.
So, there you have it. There was an area just east of this pic that was marked for "Extras Parking", so that's a good sign: either zombies or more characters! That parking area is in addition to the number of vehicles you can see parked here on the side of the road. That's a lot of cars, especially to be so near the studio!
Check out the video in it's entirety on my Youtube Channel : "ThePhoenix6430"; it's "Deadite Joe Show #7"
Thanks & I'll post more as I'm able to catch them out on a better location!