I had a another thought.  What if you took the van to a friend or
even a shop with a big impact gun and have them loosen that
nut.  Then you torque it back before driving home.  I bet it would
then be loose enough for you to get it loose again with your tools at
home.  I was once working on a GFs Honda front axle nut that was
stuck. I tried everything I could think of.  Including using the
engine torque to break it loose.  Finally I took it to the auto shop
and the guy had to get out the rarely used bigger impact gun because
the "regular" one couldn't get it loose.  I felt better then about
not being able to get it loose.  I then torqued it back, went home
and could get it off again no problem.
Edward