Where in the wall?!?! Just kidding! The cache is not in the wall, but very close to it. Please replace as found.
You can access the cache from either side of the wall, however i suggest the "AC Moore" side. High muggle area, mostly driving past though. Please be careful not to drop it, unfortunately people sometimes suck and leave trash laying around (even though there are dumpsters so close) and I'd imagine trying to find it may be tough if you dropped it.