Something to consider is that a newbie game doesn't really need to have 10 Kingdom cards. You could teach many of the concepts just by having Village, Smithy, Market, and Caravan. It'll be a boring-as-shit game for you, but it'll all be fresh for the newbie. He can use these cards to grasp the concept of actions, buys, coins, cards, and even durations.
I hesitate to include a trasher. Perhaps that could be demonstrated after the game. Take that player's deck and remove all the Coppers and greens. Now have that person shuffle and draw a few hands to appreciate density. Then when you break out the big guns, he'll be more interested in those cards that trash (and possibly learn why Develop is not as cool as it might seem).