I just changed our no name chinese made stereo with a Panasonic AVH-X1600DVD. Had no use for bluetooth so saved some money over their other models. Paid $180 at best buy price matching off Amazon.
The original stereo had A/B/C speaker selection to turn on/off living room, bed room and outside speakers. Because conventional car stereos do not have this I use the fader control to turn on/off living room and bed room and mounted an A/B speaker switch to select the bed room or outside speakers.
I also mounted an Auxiliary and USB jack for plugging in my phone or USB stick.
I wired in a bypass so all functions work in RV. Works so much better than the cheap POS stereo that the trailer came with.