Re: 730 stereo experts
If the Rosen system has an A/V output, you could use the AUX input on the front of the 730. Otherwise, a Lockpick? You could also connect the A/V output from the Rosen (if present) to a bluetooth transmitter, then select this as a source and stream your audio. There are a few good bluetooth transmitter/receivers available. I have one that runs from 5V, so it could get its power from a USB connector. I use it to send audio from my home jukebox to my audio system.
2012 Overland V6
Deep Cherry Red w/Saddle & Black
Thule Criterium Bike Rack