Cook it saturday, let it rest and pull as usual and then vacuum seal it up. I did the exact same thing a few weeks ago for my boy's baptism. I thawed the pork out a day or two a head of time in the fridge and then heated them up in a pot of water on the stove before putting them in the crock pot on the "warm" setting. If you need a little extra moisture, add some apple juice as others have said. I didn't end up having to add anything to mine when I did it and it turned out great!
WSM 22.5", One-Touch 22.5", Redhead 18.5" Smoke Joe Silver, Q200, "Mr. T"