We recently had the opportunity to tag along as one of the first batch of new Pioneer AVIC-F90BT navigation head units was installed. The new head unit is the most affordable in-dash navigation Pioneer offers, but it isn't short on features. We had a plan to use the F90BT as the centerpiece for a total audio transformation, with a backup camera, speakers, amps, and subs. We unloaded all of our new Pioneer gear, including shallow mount subs, basalt-cone separates, and a cool new Subthump box at Progressive Mobile Electronics in San Diego, California, and got everything else we needed directly from Progressive's stock. Peter Meyerchick was our audio technician, and did a great job of installing the system seamlessly, working within the confines of the Silverado's cab to hide all of the wiring and secure the amps in an out-of-the-way position. Check out truckinweb.com for more on the install.
Pete began with the backup camera. After considering possible locations, we settled on the top of the tailgate since it allowed for a downward angle, and also because the plastic trim would conceal it. | 
To make things easier, Pete removed the tailgate handle. After drilling the plastic trim, Pete used the same holesaw on the sheetmetal before opening the top of the hole with shears. |
The camera has cam-like washers that allow aiming, but we went for a flush mount. Here's Pete threading on the locknuts. | 
A step bit was used to enlarge a factory hole in the tailgate. You can see the taillight's been removed to access the wiring. |
A corresponding hole was drilled into the taillight cavity and both the power and RCA cables were fed through the holes with protection from this rubber loom and some silicone sealant. Extensions were needed for both power and RCA, they were wrapped with electrical tape to keep from coming undone. | 
Pete used split loom on the RCA cable, ran it up the length of the frame with the factory wiring, and ran it into the cab through a rubber grommet under the driver-side floorboard. |