A keg will take longer than a few hours to chill- I've found that 5 gallons of beer often takes overnight to get to 40 degrees in the fridge. I'd chill it before hand.
And even in a clear beer, the sediment will stir up enough to make the beer pretty cloudy and sludgy the first few hours.
There is something that I do that works really well. I chill the keg (carbed up and ready to go), and let it sit until it pours clear. If the keg is chilled for 48 hours first, the second pour is pretty clear if the keg isn't moved.
Then, I get a second sanitized keg, and just "jump" the first keg into it. That is super easy- a black QD, about 4' of beerline, and a black QD. Add some co2 to the receiving keg, and pull the pressure relief valve. Turn down the regulator to 2 psi, and purge the first keg. Then take one end of the jumper cable and put it on the "out" of the first keg, and put the other end on the second. Keep pulling the pressure relief valve on the receiving keg, to keep the beer flowing, and you have transferred cold clear sediment free beer.
That's how I take kegs to parties and events without stirring up sediment and having foam.