I'm still waiting for my stuff but I figured I'd get some work done on the install yesterday to make it a bit quicker once it does arrive.
I'm not going to show how to get the old system out as that's already been done very well.
I cut the top of this metal bracket off. Using the notches on the side as a guide for my air hacksaw. This way I have nice rounded edges and it doesn't look like it was removed with a rabid squirrel

I didn't cut any of the plastic as I've seen others do. I dont think it should have to be cut. A double din is 100mm and the space is 100mm so we'll see how that goes...
Next i'm going to run my RCA wire for the backup cam. I bought a 25ft wire for my Quad Cab and it will run right into the tailgate. I didn't want any connections under the truck. I started on the left side of the dash by removing the panel (it just pops off) and feeding the wire through over to the radio opening. I then taped it to another wire so I don't accidentally pull it back through while i'm running the rest of the wire.
The next step you need to remove the a pillar/rocker trim by pulling up on it. Its just clips that are pretty easy. Then pull the b pillar lower trim loose at the bottom and finally the trim for the rear rocker. This way we can run the wire down the rocker along with the factory harness.
Then we need to get the wire into the well under the rear seat on the drivers side.
There is 4 plastic clips that hold the interior trim in the well. Just pop them out and pull back the trim. I ran my wire from under the trim / under the carpet into the well just in front of the seat bracket.
Inside here you will find a plastic grommet that you need to drill through to get to the underside of the truck with the wire. I pulled it off to do this but next time I would just leave it in as it has a factory sealant around the edge that i've now messed with.
I ran my wire through and sealed it all up with body seam sealer. Including gluing it in with the sealer.
I then ran the wire over the fuel tank and over the spare tire zip tying it along the way. You dont want the wire hanging down it will look like crap and end up getting ripped off.