"Livin' on Reds, Vitamin C and Propane" is the sixth Christmas episode of King of the Hill, aired in the show's eighth season.
Hank is helping his mother Tilly move into her new home in Arizona. She tells him that she left quite a few things behind that she inherited from one of her recently-deceased friends, so he orders a moving truck which turns out to be bigger than he expected. Bill, Dale, and Boomhauer want to come along but Hank tells them that only Bobby is coming with him. Unbeknownst to him, Bill, Dale, and Boomhauer sneak inside the truck the day they set off. Meanwhile, Peggy and Luanne try to come up with a new Christmas carol which involves Hank and Bobby delivering Christmas presents in the truck.
Hank and Bobby stop at a cafe to eat. Before they take off again, and Bill, Dale, and Boomhauer break out of the truck by shooting some holes through it and they are severely dehydrated because of the heat and that they brought nothing to drink, Hank is furious with them and that they cost him some time in the trip and the other truckers make fun of him for it, later that night Hank is getting tired so they stop at a gas station to get some coffee but Hank has already fallen asleep by the time Bobby gets back so Boomhauer drives while Dale and Bill tell him where to go. They come across a highway clearance and they panic because they don't know how high the truck is and they end up driving up a mountain and using up the fuel, when Hank wakes up he is shocked and furious and he decides to call some real truckers to help them, but then they decide to use what they have using oil from some lamps to refuel the truck and make their way down the mountain during which the mirrors get broken.
They eventually make it back down, taking shifts riding on the sides because of the broken mirrors. They arrive at a truck stop to get something to eat and they encounter some truckers who heard of their journey and help them out and they arrive in time for Christmas at Hank's mother's.