As someone who has had, and enjoys, their fair share of solo midnight hikes: two simple rules. Tell someone where you're going (and have them call for help if I am not back when they wake up the next morning) and bring a $20 keychain flashlight or headlamp. That dollar level will get you a surprisingly bright and compact light, as opposed to the symbolic candlesticks that inhabit the cheaper tiers. 

Most cell phones have small lights built in, but phones can get lost or damaged easily if you take a tumble down a hill or find yourself in a sudden water entry situation. Put it in a zipped pocket that's on your person and not on any pack you may have with you. Just a little bit of light can get you out of a tricky situation or assist with signaling and you won't notice it's there until you need it.