Casey,
I used a 1/4" flat ratchet wrench with a 1/4" phillips tip installed. From the top dash access, you can reach around the mount to get to the left hand screws. If your hand is too large, you may have to remove the left dash face panel. It is secured with treaded studs (10/32) at each corner.
The Bose Lifestyle has to be on, the amplifier has to be on (the switch overhead next to your video selector box) then choose on the Bose remote which input plays your dash radio. (aux 1 or aux 2). If none of that system is still operational, you may have to install additional speakers to your replacement radio. Fred