Most lightbars have one of the mounting bolts hollowed out to run the wires into the truck that way. Or at least all the ones I have seen. then it's perfectly sealed. check your bolts, maybe you missed it?
For my light bar, did a 1" hole in the middle of the bar. Used a grommet to keep the wires from getting cut, coated all the wires in silicon, and wrapped it that plastic harness stuff. Then ran the wires across the head liner and down the passenger side. The installed a fuse box behind the passenger side rear speaker. Then have a master power line that runs under the passenger side door trim up to the starter solenoid. have to take some pics later.