A weight distribution hitch is more about restoring the weight to the front of the vehicle, that is the steering control, than it it about leveling. Mini-vans are built for a comfortable ride and therefore have soft suspensions. That said any small travel trailer will have enough tongue weight that will require you to use a WD hitch.
An Rpod might be doable. What you really have to watch for is the rated payload. Look at the yellow weight sticker in the driver door of your van. There should be something maximum load = x. Subtract your trailer's tongue weight, any cargo you'll carry in your van, the weight of all people and animals. If your cargo and tongue weight goes over the rated payload you have too much weight. Others can explain this better than I am but I hope this helps.
