The best I have done on Sandy Run is a list of bridges in GA that need repair:

Tucker Rd
US 129
US 41
Smoke Rise Dr

When I put in Tucker Rd, GA in Google maps I get a Tucker Rd in Macon, which seems too far away. US 41 intersects with this road, so there is probably a Sandy Run in that area.

I got nothing when I put in US 129 in GA. Smoke Rise Dr, GA takes me to a location at Stone Mountain which also seems too far away from your site.

I would recommend that you call the GA Archives. They may know where it was.