Richard, I installed a bus bare under the hood for convenience but could be put anywhere that's powered through a fused toggle switch direct from the battery.
This runs all additional devices used, like my radio, gps, and an additional lighter plug in the rear for things like coolers and stuff. The original fuse panel is as stock.
This setup works for me as my ignition switch doesn't have a accessory position and I can't use additional devices without the engine running.
My original rear camera was wireless but required a power source which was supplied through my license plate light, but I have since wired it to the bus bare which I picked up at a marine store..
I mounted the monitor high and tucked the cables in the windshield moulding, but this might not work for different generation trucks.
If your monitor requires a lighter plug you can always mount a separate dedicated one somewhere hidden.
I experimented quite a bit until I found a set up that suited me.
Enjoy the process,
John
