backup camera usually mounts on the rear roof of vehicle to get best viewing angle , the monitor you can choose is clip-on rear view mirror monitor or stand alone monitor. but easily wiring backup camera system is wireless reverse camera system, that no need run cable between camera and monitor, this is the source:
https://brakelightcamera.com/product-category/wireless-backup-cameras/
https://brakelightcamera.com/product-category/wireless-backup-cameras/