I used a combination of methods taught to me by BBQ Bandit and Pitmaster T. I had to combine the efforts because of my available materials and the time I had to work in.
I cooked a 12 pound brisket, sealed it in a large foodsaver bag along with some of the au jus. Then, I plunged it into a cooler full of ice to cool it down quickly. Once cooled, I put it in the fridge.
The next day, I boiled some water in a large pot and put in the brisket still sealed in the bag and let it boil for about 30 minutes. I removed it from the water and put it in a cooler and took it to the destination where I sliced and served it.
It was superb! I couldn't tell that it had been reheated.
Thanks Bandit and Pitmaster T!
Operation BBQ Relief Founding Member - I am Obsessive Compulsive about BBQ. Google it.