I did not have the same issue of the lamp not seen from certain angles as you do, but for years a long time ago, I ran my 8' pop-up within the 8 bed with no exterior light sources at all. I did not mind because it was a pop-up and I had clearance lights on the truck front. Perhaps not exactly legal to the full extent of the law, but I had the functioning important ones operable.
Maybe you could do the same route as I described above for my current TC... Then by hitting the factory plug on the camper then the running lamps will work too.
I did not want to mess with trying to hit the truck loom somewhere in the middle when I knew exactly what line is which on the flat-4.