Back when we first saw the others village and there was controversy about Ben's order: "if you run you can make it" I posted this, so sorry if you've seen it already. I thought of it again after seeing a screencap from Par Avion of Sayid's new map. Written in the upper left corner is:  Subterranean passage 20' deep.

There has to be service tunnels on the island to support that kind of infrastructure.

With all the heavy gear in the stations there is probably also a small gauge rail system (Rose's roller coaster image when they hear the "monster"?) or at least electric pallet jacks or tow motors in the tunnels. The IBM, PDP-11 era tape drives alone weigh more than a fridge. Building old mainframe computer rooms and installing scientific equipment and shield rooms required it.

The logisitics of keeping roads open and passable in a jungle environment is enormous. You would need a full time road construction crew. My bet would be that the main entrance to the service tunnels would begin at a deep water port, which is also a necessity.

The power and communication infrastructure has to be underground also. Power consunption must be huge and the LAN/Ethernet backbones of the early to mid 80's were "thicknet", a thick 1/2" od cable, usually orange or yellow (although there were dark shades used for mil aps) that needed large "vampire taps" for each node connection. If it was installed in the late 70's it would consist of telephone trunk lines and a PBX. Not something you would have outside in a jungle environment unless it was housed in conduit and large splice cans.

It seems that the others may control the tunnels up to the Staff, as this was their jump off point where they kept their rag outfits. It would also allow them to move in and out of the barracks compound quickly without needing to deactivate the "Brain-Fryer 5000" system.