My two bits:
    I built a trailer in 1990 to haul a flying wing with the vanagon, and have
hauled lots of crap - ex girlfriend's stuff and all.
*  If your hitch is mounted low and close to the rear axle, good things happen.
The low force vector will have very little effect on front end dive during
braking, depending on where it is relative to the rear axle centerline.  The
closer your hitch gets to the rear axle (front to back direction), the lower the
forces are that act on the yaw component of steering.  Ideal would be right at
the axle.
*  Tongue weight and inertia added behind the rear axle help stabilize the van
in crosswinds.  Our vans are like arrows flying backwards - weight aft and
feathers first, because the center of mass is behind the center of aerodynamic
pressure.  The front wheels work hard to keep us going straight, and you sure
notice it when the front end is worn out.
*  Trailer design has a lot to do with it.  The best way:  long tongue, wide
axle, low CG of load, place axle springs such that when the trailer leans, the
shackle movement shifts the axle to add countersteering, and have a low polar
moment of the trailer and load if possible.

I've towed about 1,500 lbs with no problems at all other than the slowness.

Randy

Rich Burdick wrote:

> >Bill wrote--
> >"If you paid attention in physics ...
>
> >I don't have time to write out all the details ...
>
> >In particular, during emergency braking, ...
>
> >If the load is tethered to the rear of the vehicle, the valve may not sense
> >the forward shift in mass accurately, and in fact, the rear of the van may
> >be likely to have an increase in load, as the mass on the trailer tries to
> >remain in motion, and shifts forward, pressing down on the tongue.