If you only remove the radio with the tool that came came with your information package, you can see the wiring but it is still hard to reach. You will notice that the cabinet forward of the sink where the TV mounts has a false bottom - Removing the bottom out of the inside of the cabinet will expose the wiring, the paths they take and give you better access.
I used the 12VDC outlet to power a 300W inverter for my 21" TV/DVD combo - I'm not sure what your audio sub draws, but something like mine may be enough to not need additional power runs.
