Although the above is probably your problem, here is a video on how to remove the key cylinder.
At 2:09 in this video you can see the end of the cylinder, that turns the brass gear, that moves the actuator. The actuator is connected to a rod that goes down the steering column to the ignition switch. It is possible the end of the cylinder is twisted and not turning the gear. You should be able to see this after pulling the cylinder. If you're still unsure, you should be able to turn the gear with a screwdriver. If the actuator is ok, the van should start. If the actuator needs replaced, try to make note of the position of the brass gear. TAKE A PICTURE. It can be a real PITA to get the timing on the actuator and the brass gear correct.