[UPDATED WITH FINAL CONFIG] Here are some pix. I couldn't find a way under the cupholders, but as soon as I found the side access, I stopped looking. From behind the radio I went left to behind the carpet panel. Then there is a direct path from there up to the area under the shifter. With the Media Cover (under armrest) removed it's straight access.
Plenty of room to pass from under the shifter to the armrest console:
Easy routing; same on passenger side:
Plenty of room under the shifter to store excess cable
Regarding the locations of the filed down areas highlighted by red arrows, on the Armrest console there is a thin backing that would interfere with this hole, unless you slot it more. To avoid hassle, check your backing and pick a location where there's no interference...see following pix.
Depending on your Aux Cable thickness you may need to max out the slot depth as shown here:
My Aux Cable was too thick so I needed to modify the armrest console as well:
Pretty rough, but hard to get to, you also want to file down some of the armrest console for the USB pass through:
All done.
I went ahead and order a Mic off Amazon...I was going to install an upgraded aux cable and while back there I thought I might as well as connect a mic, in case it's needed.
Jeremy