It is certainly easiest to understand how the adjusters work when you can look
right at them, but I can sympathize with anybody's reluctance to buy a puller
and learn a new skill just in order to make the adjustment.  One good interim
step would be to buy the John Muir (memorial) "Idiot" book.  He devotes MUCH
more space to brake adjustment folklore than Bentley.  He also explains how
to get the drums off without a puller, which involves a chain from one lug
bolt, through something heavy (I always used a spare tire and wheel), to
another lug bolt.  Swing the wheel a few times to slam the chain out taut and
the wheel walks right off.

In answer to the direct question posted, the star wheels are not directly be-
hind their access holes (if I remember right) but kind of slantwise.  But 
nothing but practice will give you the sense of what a star wheel feels like
when it's turning, vs. what a star wheel feels like when the screwdriver is 
sliding off it.  And that practice is dramatically easier to get by sight than
by feel.

Good luck.  And don't take the van to a shop for this.  Your van WANTS you to
do this kind of thing.  So does your wallet.

B.
6-cylinder 81 Vanagon "Toy Box"
77 Porsche Targa "Frog"
nameless Japanese car x 2