Ken,
A friend of mine, serious racer type dude, has been hanging a Yakima
rack with four bikes on the back of his Westies for years (probably 15
years to be exact and at least three campers).  His latest rig, a
EuroVan, has the same setup. He doesn't have to worry about taking out a
McDonald's drive through and there is little wind resistance.

I intend to do the same, when I get around to it, on my new-to-me '90
Westy.  Will use gutter less mounts on the rear door.  I'm curious to
see if there is enough ground clearance to hang a tandem.  Guess I'll
find out how strong my new door struts are as well.

Years ago, my goin' to Moab rig was a 1970 Westy on which I bolted a
Yakima on the stationary part of the roof which was behind the poptop.
That worked out real well... could reach the bikes from the inside when
the top was up through the screen and I used the little four-legged
stool that came with Westies in those days to reach to rack from the
outside.

John,

1990 Westifalia
Merlins,  Rodriguez, Specializeds, American, and soon, a Burley trailer.