Got prototype setup running -- tablet controlling music and basic audio commands.

Sadly previous owner did a crap job redoing part of the wiring harness under the hood and a short between a ground wire and an aux power caused the entire length of the ground to vaporize and melt a few other wires in and shorted the whole thing out (whilst I was driving no less)... That was two days ago, I've got most the wiring back in place and hopefully tomorrow I can start getting some pictures and documenting the install of some of the fun stuff.