Is there any way to completely turn off the screen of the D3 while still keeping the audio running? (Reason I ask is because I go to drive-ins alot, and it's very distracting during the movie)

From an A/V source:

Menu->Settings->Screen Off

Cardboard and tape

Basically what you are saying is that the light emitted by the D3 allows people on the outside to see what you and your girl are doing on the inside?

yeah basically, but some dark tint works miracles

may be different but if you hold the screen button on mine the screen turns off but everything still functions