Plastic window pillar trim just pulls off there are a few clips on it, the metal clip sits in the metal pillar and the lugs are on the trim. You can get the wire in behind without removing if you pop the door seal off and push wire in behind.
When I did my camera I removed trim , both sun visors ( two screws ) to free head lining to get camera cable in behind headlining. What I will say is be careful you don't pinch the cable on metal clips that secure pillar trim, best to tape to side edge of metal pillar so it's not moving around when you refit trim.
As I said trim comes off with a bit of effort, use trim tool but if you haven't got one some strong fingers will do lol. I have camera wire and the wiring running from my Honda interior light to my footwell lights and you would never know it's there. I hard wired my camera in behind radio as I don't like having things plugged into cigarette lighter.
Hope this helps Bren