for the cables, I usually leave the outers in, remove inner cables, levers, etc, then run an inner back through the outer, and remove the outer leaving the inner cable fully routed. tape it the ends to the frame to stop them pulling through. I've never done that with maguras, but I guess if you bled the oil out and removed the levers and pistons you could do the same, an inner gear cable would probably fit through the hoses OK, make sure you solder the end first so you don't scratch or puncture them from the inside though