Does anyone know how to get the cable into the back of the unit? 
And then into the glove box?
It's all pretty easy.
Ideally to route the cable into the glovebox you'll want to remove the glovebox, so you can fasten the cable back and avoid rattles. The glovebox has torx screws on the underside, along the top, and one cheeky one behind the cover above the ashtray. Undo all of those, then the glovebox comes out, but watch out for the wire connections to the glovebox light, switch, and footwell light. You also need to disconnect the small rubber air hose.
Radio is also easy. You'll again be working with torx screws, along with a stiff but relatively thin trim lever. I use a tyre lever, which by luck is especially pointy yet stiff (designed for downhill tyres...). You start at the top of the centre console, and gently lever out the large diffuser. You then undo the single torx screw to remove the air damper. You then undo 2 torx screws that hold the twin air vents, and gently lever up the bottom of the vents either side of the radio (towards the top). Now gently usher the vents up and away from the dash.
With the vents removed, you now gently and progressively lever out the radio and heater control infill trim. This will expose the 4 torx screws for the radio. Remove these and the radio slides out.
It really is easy to remove the radio - you'll take a while the first time as you learn the force required to remove the trim, but it'll take 5 minutes the second time.
There are probably some how-tos knocking about with pictures, if you want more clarity.
