Sorry guys. There isn't much to see in the backstage areas at SFGAm. Dumpsters, the back of buildings, thats about it.
The Magic Kingdom offers in WDW offers a plethora of backstage tours, ones that will take you in the tunnels under the park, architecture tours, and steam train tours. If you want to see behind the scenes at a theme park, go to WDW and take one there. They are great.