Start a House Rules game with Forced Play off and Draw Until Play on - this means you can draw cards infinitely even if you have one you can play.
When it comes round to your turn, just keep drawing cards until you get a Wild Draw Four and play it, usually they won't challenge even if you have upwards of 25 cards; if they do, just keep drawing until you can do the same again. Repeat if necessary and an easy 10 gamerscore will be yours.