Get a smart phone
I have a NUVI 760 which I can put my music on via a SD Card, or use an old iPod, but opted to use my Motorola Atrix (Android). My setup is GL2WAY for the CB and have the GPS to MIC option installed. I have the GPS audio out and mic in through the GL2WAY, and my phone bluetooth connected to the GPS. My phone has the audio out hooked up to the Aux. With this configuration I can make/take calls through my GPS which I like cause it has the larger buttons. I also like the GPS better for maps as they are easier to see. And I have AT&T, so I have to assume I will not have a signal more often than I do. I can use my phone for music and podcasts when cell and/or AM/FM reception is poor. So answered more than the music question, but I do think the smartphone is the way to go. Of course that assumes you are also willing to pay the much larger $$ for the data fees...