If I had to ride at night frequently at odd hours, I'd think about riding on the roads, near the center (exactly where I wouldn't want to ride during the day). There wouldn't be too much car traffic and you'd be out in the open, ideally with decent street lighting. The problem with the trails at night is too many dark areas that provide easy cover. Though the main issue with that idea is the occasional car could be just as much a threat as anyone lurking in the darkness of the trails.