I ran 4 gauge power and ground wires off of the battery through a bushing and into the bottom of the toolbox...stay dry.
I used a fused power bar (for car stereos) and ground bar mounted in box. All led's and winch run to those. Stereo and GPS go to the harness so they're switched power. Wanted some accessories to have ability to run regardless of ignition. Didn't want too much spaghetti under hood.
Accessories are easily added by running wires into bottom of toolbox. My 2 cents.