You don't think anyone's actually sleeping in that thing do you? Perhaps whatever agent gets a night shift watching the van as it sits in hotel parking lots, perhaps.
In fact, I doubt Hillary's even spending much time in it at all. She's probably going from place via helicopter/jet and meeting the van a few miles out from each stop so she can get into character.
I wouldn’t be surprised if Hill uses the van — she probably really needs her naptime in between events. Besides, it was cheap. She inherited it from Bill — just had to peel off the “If this van’s a rockin,’ don’t come knockin’ bumper sticker.