I have taken Backstage Magic ($200) twice, 3 years apart. The first time, we entered the tunnels from the main entrance, behind the park. We toured the make-up and wig deprtment, the "zoo", and then DACS and Parade Central, then walked under the castle to the central stores, then up to Main Street. It was outstanding!
Then, this last time, we pulled up behind main street, went down to the big map, saw some walls and walked right back up. Worst tour ever.
Keys to the Kingdom did the same thing. We saw a trash pipe and headed back up.
I understand that the CMs don't like you invading their space, or ruining the magic, but at the same time, that's why I'm down there! I paid to ruin the magic for myself because I'm more interested in how things work than what is actually working at this point in my life, HAHA! I would still respect their privacy, but they're just hallways.
As for the guy who wants a SM tour, ME TOO. I wish they'd do some afterhours or before hours tour where you got to see INSIDE rides, like really INSIDE. I'm talking computer rooms, control rooms, pump rooms, under floors, behind walls, etc. I'm a construction guru and technical nerd! I want to see how they work! I would pay nearly anything to get a tour like that!