I'm a 34-year-old white girl and I've lived at 129th and Lenox (Malcolm X Blvd) since January. I've walked from the train at 125th at a variety of hours and have never had a problem. Lenox is always super busy, so I've never been out of sight of other people. And there are always cops stationed at various corners (which could also be a bad sign). I've explored a few of the areas around where I live, and the feel of the neighborhoods changes with every block. But I can tell you my few blocks are great!
I hope that helps! I wish I'd known about this site before now!