Anyone who has spent anytime riding in the back of a Volkswagen Bus on a hot summer day can tell you that putting a bunch of fixed windows on the back/sides/top of a metal box turns that greenhouse into a oven. The better solution is to skip the bakin Bus and pickup a Corvan equipped with several rows of rollable windows --like this 1962 Chevrolet Corvair Greenbrier Van offered for $6,500 in San Diego, CA via craigslist. Tip from FuelTruck.
In 1961 Chevrolet introduced the Corvair 95 light truck version to join
the 2-door and 4-door Corvairs released in 1960. The Corvan was
available as a Greenbrier Sportswagon,
Loadside (conventional rear loaded pickup) and the Rampside (uses a side
door to access the lower front section of the bed). It is the poor
man's alternative to the preposterously expensive VW
Bus/Van/Transporter/Kombi and offers the same cab-over sketchy driving experience that you
will never want to drive it fast enough to have the rear swing axle suddenly decide to kill you.
The coolest thing about this Corvan (figuratively and literally) has to be the roll down side windows, there must be 6 window cranks in that thing! Imagine offering a kit to convert those to electric and being able to roll down 6 windows at one time. The second coolest thing are the premium 1962 wheelcovers from a full sized Chevy.