Before you know it, you'll be riding the whole distance. That's an easily achievable commute. Be warned, riding at night is addictive. But start saving money for a brighter headlight. Brighter is always better. And redundant taillights are a good idea. And reflectivity.

Bike Nashbar regularly sells their "ATB panniers" at a heavy discount. I think I got my pair for TWELVE BUCKS and they've held up well for several years. Not flashy. Kinda dorky black panniers. Dorky is anti-theft insurance. A thief will steal a shiny WalMart MTB before they look at my purple Bridgestone XO-2. LOL