you can probably run it through the factory grommet that all the stock wiring goes through as there was always plenty of room for me to run a 4 awg amp power wire through them when I was installing. Otherwise when it comes time to drill you just need to find a spot that you can see on both sides. Say it is 3" to the right of the brake cable on one side, look 3" to the left on the other side to see if it is clear. It is also helpful to make a small hole first and then you can shine a light through it to ensure it is where you want it. Small holes are much easier to fill/fix if it is off a bit than big holes. I normally do a small hole first and then use a stepper bit for the larger.