Does she lag 100 to 200 blocks away? It'd cost energy, but you could run a long cable to an outpost outside the laggy zone. And then you could save energy by putting a Dark Cable at the source and controlling it with a redstone signal from the outpost. If you have the Player Detector block that emits a redstone signal when a specific player is online, there'd even be no hassle to this design.
For a friend of mine, to save energy for his tiny network (powered by one hobbyist steam engine), I designed it to cut the power to the controller unless he stood on a pressure plate in front of a terminal. It was very convenient. You could do this as a simpler option.