Where's McGyver when you need him? He wired a sack of 'taters in series to a cigarette plug, let it trickle charge for awhile, then jacked up the bus, spun the wheels in gear to add some additional charge, pulled it outta gear, spun the wheels as fast as possible and popped the clutch in gear. Either that or he pulled a battery from one of the other abandoned buses in the field and got lucky.