If you don't want the van then it's no problem. If it's running, drive it to a near-by police station, leave the keys in it and walk away. They'll take care of it for you. There is no legal trail from the van to you and the registered owner will say he sold it. The police will impound it and sell it at auction. Maybe they'll even give the proceeds to a local charity (Hey! A guy can dream can't he?). It's out of your hair.

Not running? Pull it out to the street and call it in as an "abandoned vehicle".