What's the point?
I have no nav, but I have the iPhone/BT through the stereo.
Current setup:
iPhone 4s set up via BT for phone only
iPod separately docked in the pouch and connected to the USB port via the standard Mac cable
Can anyone see a benefit to me docking the phone? 
It seems like it would be a PITA to remove the case each time and dock it. Right now things are pretty easy. I hop in and the BT pairs fine. I leave the iPod in the car and I can navigate those tracks fine via the radio.