Temp back up cameras for old vehicles and trailers

[Lynn]

First, I am horrible at backing up trailers. Getting better, but still need some help.
Would like to purchase a couple of mini cameras that I can view on my iphone with an app. I figure I could put one on top of each tail light bracket and get a good view of what I am about to run into.
Would like something I can do split screen so both are viewable at the same time.
As a bonus, I could place one on the tailgate of either the El Camino or the Yukon XL when hooking up, as neither has a back up camera.
Any bright ideas?