for me I like the radio constant +12. I run radar detectors off cig wire ACC as long as it's not constant on. Ground anywhere under the shift plastic is good enough.
Behind the ashtray and power ports there are plenty of lines for what you need. But it's personal preference I think.
I like certain things to behave like a retained accessory port, RAP. So that your radio stays on until you open the door, or your cig lighter stays hot until a door switch is activated or you push a lock button, or key fob, It depends on how you want your new component to behave, and which fuse you want to check when something doesn't work. I think people forget that part.
I don't remember a constant +12 around the ashtray area, But I'd bet there is one.
Edit, I would just put the illum wire with the ACC line you use. Unless you want the rheostat capabilities that come with dimming the dash lights. (if what your installing has that capability to begin with)
