Does the rear view mirror show you the outdoor and/or indoor temperature in a corner? I've seen some manufacturers install the rear view mirrors just for that. I use mine to figure out what I forgot to secure when I hear a bang inside the rig behind me.
One thing I've seen other RVers do (mainly Class Cs and pickups towing 5th Wheels) is purchase another rear view camera (wireless) and use something like the Haloview BT12 display mounted over the OEM rearview mirror. That way instead of looking down at their dash to see behind them, they look up over to the rearview to see the monitor:
I'm debating doing this on my Wayfarer as the Kenwood that is in the dash is mounted facing straight back vs angled towards me and there is often glare on the display.
Best,
-Mark