I upgraded my back up camera to color and ran a new cable under my motorhome along the frame rails with some wire bundles. The hardest part was getting started at the rear cap. I was able to remove my rear red running lights and a stiff wire to pull the new cable to the side then ran it down to the tail lights then to the frame rail to the front of the vehicle. Then it was an easy pull through the firewall to my new 9" flat screen color display.
My RV is 34 feet long and the cable was 66 feet long and I did not have that much wire to spare, maybe a few feet. You need a longer cable than you think. Use a bunch of wire ties to keep the cable in place under your vehicle.
I bought mine from these guys. The color is off a little around the edges but works great. The price was right $ 114 for a 9" display.
06 Hurricane 34FT WH W20 Chassis 8.1L 120K, Steersafe, Koni Shocks, DIY Trac Bar, Tri-Metric 2025RV Battery Monitor, 4-6V Batteries, Scan Gauge 2, Crossfires, 735W Solar Morningstar MPPT-60, KVH R5 In-Motion Sat, XM Radio, 07 Chevy Malibu Maxx Toad, Falcon 2, Brake Buddy, Escapee