It's not too demanding on the free time. You can drive your ten in-game journey legs, and then leave it for 10 real world hours, and still maintain maximal efficiency.
I'm trying to create network flow maps for the european terminals and determine an optimal delivery route I'm a geek, I know!
You should start a team based on the flow maps and kick some butt.
Edit: I wonder if there are rules about how many characters you can play at once?