San Francisco Transbay at night?

Walking around late at night may not be safe for a male or female. Perhaps you could fly to Reno instead of taking a bus. Inside the bus station would probably be safer than walking around outside. Don't walk around with a map in your hand (you'll look like a tourist). Just keep it in your pocket and take it out only when you need to look up something. This is good general advice in any city, not just SF.