In a perfect world...
sounds like a great idea. I had a similar one when I moved to Colo Sprngs and lived at Ft Carson for 3 yrs. I talked to the legal dept on post and a slew of others about this. Hell, I even have the necessary security clearances (from my prior service). No bites, and I hadn't even thought about money. I just wanted something to do (my Ex was stationed there, after I got out of the service).
I went to school instead. I think that was the better choice.

The biggest aspect would be time: are you a student as well as a courier? If so, you'll need another person to go hot when you are in class. Having another person on board: make sure they know the risk and liability of the job. Last thing you want is John Q Public coming after you for something your partner did. Or even worse, your partner's parents suing them b/c he slid under a vehicle making a Friday night beer drop and broke his spine. Or what about a bunch of Frat boys wanting to f*ck with the guy who didn't quite get their mid-term delivered on time b/c of the weather?
I know these may sound outlandish, but they may come to fruition.
Just something for you to consider...