I did it, and it is quite simple. I was **** about it because I wanted my wire out of the rain, mud and muck, so I ran it inside the frame and any enclosed area's I could fine. Simply hooked it into the battery and started running it down the drivers side of the truck.
When I got to the bed, there is a hole in the drivers side rear about half-way up the tailgate on the inside 'flange' of the bed. That is where I put my recepticle.
Also, make sure that you use a water-tight, or otherwise a 'Marine' application to avoid water + electricity = bad problems.
2010 SVT Raptor, Tuxedo Black -- 6.2 V8
2004 Mustang Mach1, Torch Red -- 4.6 4v V8 -- 5-speed -- way too many mods