Courtesy Lamps
NON-STANDARD WIRING - DO NOT USE THIS DIAGRAM FOR DIAGNOSIS!!!
IF THE IMAGE IS TOO SMALL, click it.

I'm adding several lights (including a spotlight or 2), so I'm upping the fuse to 20A (maybe 25), adding a new run to the A-pillars & roof for a CB, and relocating a run from the splice to the fuse block to reduce the load on the original wiring.
I'm also adding a relay to turn on the outside cargo lamp with the reverse lights, and a pin switch to the tailgate jamb, but neither of them will increase the draw on the stock circuit since they simply trigger the same stock lights as before. I might add some underdash lights to S299 & S305 , but they'll be too small to matter.
The stealth switch simply disables the driver's door switch so the only light that will come on is the one on the switch. If the switch has 3 terminals (as most lighted SPSTs do), I'll jumper the NO & GND terminals. But it won't interfere with any other courtesy light switch - they'll all override stealth.
The bumper lights will probably be reel lights, like the new hood light, or they might be the smaller GM reels.
See also:

.

This shows another little mod: