I don't have the GC, just a wrangler, so don't want to reply out of turn, but I wouldn't sweat the routing of the brake cable too much.
The brake cable runs through a sleeve similar to that on a bike, you route it around obstacles then fasten it down tight with cable ties. As long as you avoid sharp bends it's fairly easy to route. For me it was pretty much a straight run to the front, then a left-right jog to come out near the middle of the bumper. Just make sure the cable moves freely before and after you tighten everything down. The sleeve doesn't move during operation.
The breakaway could be more critical. This doesn't run in a sleeve, it's still fastened down, but is designed to pull tight when used (breaking the cable ties that hold it down), you have to make sure that pulling it tight doesn't bend or sever anything critical (like brake lines).
The breakaway does run to the drivers side connection area on your baseplate so it's a pretty straight run on most vehicles, pulling it tight shouldn't do too much damage. My thoughts are if the breakaway ever does get activated, I've probably got bigger issues than a little damage, the Jeeps probably a goner anyway, I'm just saving it hitting anyone else.
1990 Glendale Royal Classic
2005 Jeep TJ Rubicon