I wrote MotionX and they replied: I had asked them about being able to view current speed as well as the auto-lock issue:
"Thank you for contacting the MotionX team, sounds like a great trip. A few other users have asked to view the current speed on the maps, the team is considering adding this feature in a future update.
Also, I will talk to them team about keeping the App Radio screen on after auto-lock is engaged. Perhaps this is a feature we can include in a future update. Thank you for your feedback."