Music in and out of the interstate

I think I know the answer but just want to make sure. So thanks for listening...



I enjoy easy listening music in the morning but don't want to use the chassis battery.



I'm guessing that the Kenwood in the dash is only powered by the chassis is that correct?



Any suggestions?



I'm not opposed to using an old school battery operated "boom box"



And any cool products out there that could pipe music outside of the Interstate in

an elegant way?



Thanks



Ben (Gamper1)