You can route the power wire into the cabin through the teardrop shaped hole, you just pop the black rubber thing out and punch a hole in it, then stick the wire through and put the rubber thing back in place (i'm not sure if all the contours have that hole available, but check the right side of the firewall). Once in the cabin, you can route the wire to the back by going underneath the black weather seals, i'm not sure how well it will fit though. Remember to use plastic wire loom to protect the wire in the engine bay, just to be safe.
