A friend of mine hacked his Mazda 6 car computer and installed codecs for Flac and modifications. Most of these car computers run Linux OS, so at least in theory you could get JRiver running on the system.
It wasn't a hack for the faint of heart. At one point he had a 100 ft Ethernet cable running out to the car for several consecutive days.
Maybe run a wifi pi server and connect to the
HTML 5 panel interface?