The usual safe sources vary, but keyless locking usually does this. Even if you don't have that there may be a place for it in the fusebox with a 'hot' terminal installed. Horn is another good place to check. I don't think an 04 will have full computer-controlled power but some circuits might have delayed shutdown after ignition off and door closing.
Best way to tell which to tap is using a LED test light or a cheap DMM- either is just a few bucks to buy. Or you can ask on a car-model-specific forum; Google will bring up many. For a dashcam's low power draw any circuit with a 10A or larger fuse will have enough extra power to run your cam. Use either an "add-a-fuse" tap or inline fuse on the cam power wire to protect the car circuit, that should have it's own 2A to 5A fuse.
Phil