.........By the book, the Vanagon does get all four wheels aligned.
However I've never seen anyone actually do it.! .......
I've had my '90 into the local dealer (Campbell Nelson, Seattel) for
alignment twice, once when I first got it (and it needed alignment bad)
and again after an encounter with a lane divider.  They did the rear
both times (needed adjustment the first time, checked OK the second).
So some reputatable dealers do align both front and rear.