Dan,

of course by now you know you can undo the outer CV joint screws in place
with an extension,
AND, I would like to add 2 things :

1.  if you have 6 - point allen CV joint scews do not
  install them back in but instead get the later type
  12- point allen screws - they never strip out,
and the 6-pointers always do.

2.  ( well it's going to be more than 2 things )
   if a CV joint or any allen screw is really stuck,
before you round it out with your 6 mm allen socket,
give it some really , really hard whacks with a big ball been hammer -
that jolt will break the bond of the
theads making the bolt able to unscrw. 20 whacks, even.
Usually I hammer on an extension bar, rather than trying to hit the allen
head screw directly.  This really works.

The next alternative for a rounded out allen screw is to unscrew it with
a cold chisel and hammer.  You cut a notch in it and hammer at an angle
to unscrew it.
I've spent as much as 30 minutes on one screw in the outer CV's , but
they can be unscrewed ( and ruined )
this way.

3.  HOW TO KEEP ANY CV JOINT ALIVE FOR YEARS AFTER
  THERE'S A HOLE IN THE BOOT :

go to a motorcylce shop and get motorcycle CHAIN LUBE.
 this is a very, very sticky penetrating grease,
and spray it in the hole in the boot, ideally with the
wheel free to turn so you get it everywhere in there.

I have kept an inner CV joint with a shot boot alive this way on my
Mercedes for 7 years, and it's a helleva lot harder to replace a boot on
that car than just undoing screws.

Lastly, make sure the outer Cv joint screws, especially the outers, are
tight enough.
Many times these get loose, eventually 5 fall out and then break off the
6th one ( if you are unlucky ) and also, the van won't go when this
happens.

  just be real careful under cars.
 A FLAT CONCRETE SURFACE, a floor jack, and solid
JACK STANDS ( never use roll-up ramps ! ! )
 are essential for any work under the van.

   Scott