There's a few messenger places that do night deliveries. Check around. As for leaving the office job... do whatever the hell it is that makes you want to get up in the morning. You can always go back to the office job if you want. Life is too short to be wasting away in cubical hell.

I love the look of envy on those office drones faces when I rush past them as they smoke their cigarettes during lunch hour... always makes me smile.