Greeting everybody!

I've been lurking in this forum for years without posting much, but now I really need some help, so here goes. I've been installing an Android computer in my EP3's dash in place of the stock radio to bring the car into the twenty-first century. This is the unit I have installed: https://www.carjoying.com/us-warehou...entertain.html
Because of the tremendous flexibility of having a computer with a 7" screen in my dash, I am adding recording video cameras looking four directions from my car which will be viewable on the display. In addition I have a IR low light sensitive night vision camera I want to mount in the grill together with a 950nm (IR) spot light. I have everything installed inside the car and am now trying to find a place to snake the wiring for the night vision stuff thru the firewall. Does anybody out there know a good place to get some wiring thru the firewall? Looking behind the engine there is a wiring pass-thru with a big rubber seal in the firewall just behind about cylinder 2, but I cannot see the same pass-thru from inside the car. I'm thinking that I can maybe put a large enough hole in the rubber grommet/bellows next to the wiring bundle. An RCA connector is the biggest item I need to get thru the hole, so I need some space. Is there another, better way? I've also been looking inside the fender with the door open and if I could get the wires from the engine bay thru the fender, I could penetrate the body at the door wiring pass-thru. What do you guys think? Is there aother place I haven't thought of? Any ideas how aftermarket installers get wiring thru the firewall?

Thanks in advance for any help,

AceEngineer