I suppose the budget office stops just short of copping for local accomodations during the week after spending a butt crack load of cash hauling all that shit out there and back every day ... oh wait - somehow a daily 4 hour round trip is cheaper.
Stay where? The nearest hotel is in Primm which would only save a few miles. And they probably want to keep their prototypes locked up at night and not left in a motel parking lot.