Let me add a strong 2nd to Don's endorsement of the Duluth Trading "Cab
Commander" seat back organizer.  I've been using one in my Westy for nearly
10 years now ever since I saw one in Roadhaus, Larry Chases's Westy.  Very
rugged, plenty of well designed pockets and spaces and just the perfect
size for a Vanagon seat.  Mine has faded a little in spots where the Sun
gets to it year round but no other sign of wear.  And it is on the list of
"Best Additions" to my rig.