I was at the Big Lots store the other day and saw some things to use in the
Vanagon for cheap.  I bought a 12v Fluorescent 8 watt trouble light for
$5.  It is one of those round stick type lights inside  a clear plastic
tube.  There is a shiny metal reflector along the bulb on one side.  My
idea is to use those springy brackets that are used to hold things like
brooms and mops to mount the light.  The light will clip into 2 of these
brackets mounted somewhere toward the rear of the cabin.  Rotating the
light will adjust where the light falls due to the metal reflector in
it.  I am thinking of also putting another set of the clips over the sink
area so that it could also be mounted there.  Maybe another set of clips
somewhere else?  I will leave the hook on the end of the light, so that it
can be used portably in other places.  It will need to have a switch added
to turn it on and off, and some way to manage the cord so it isn't hanging
all over the place.  Perhaps some kind of reel thing like in a vacuum
cleaner cord.  It is pretty bright, box says it is equal to a 40 w
incandescent bulb.  The light quality is not real pretty though.  Typical
bluish green cheap fluorescent.  Perhaps a filter could be added to enhance
the color?  If I get this thing set up I will post some photos.

the other thing I saw of note was a 1 amp battery charger for $7.  I
already have such a thing for my aux battery, so didn't get one.  I'm sure
it doesn't adjust its voltage, so couldn't be left plugged in
indefinitely.  Mine is the brick type transformer on the plug.  This one
was a separate box, with AC in plug on one side and 12v out wire on other
side.  Looked like it could be easily mounted out of the way in your van.

Big lots products seem to vary by store and region, so you may not find
these things in your store.  www.biglots.com has more info.

Edward  (not affiliated w/ biglots, just like bargain vanagon improvements...)