video/vcr in 1998 dodge dakota

I have the entire system, to install a flip down 6" monitor, VCR and camera

The help I need is looking where to hook up to the power supply.

I have three wires on the system RED / blue/black, I understand the red is constant on, the blue is on only when the key is on, and the black is ground

The video I'm installing in the headliner, the camera is going on the dash

the VCR is being installed against the rear quater panel on the passenger side, the question is where do I run the power from??  I though of connecting to the dome light, but that goes off after a certain time, do I need to run clear to the fuse panel on the drivers side, and actally wire into the block??  thru the headliner or under the carpet

So since this is a truck, do you suggest running the wires via the headliner

or going under the carpet, since I have to take the headliner out anyway

to allow for mounting the flip down screen, it seems reasonable to run the wires via the headliner.

What do you think?