This subject comes up on the list from time to time, and I can only offer
my personal experience.  

I have never experienced, nor heard of, a bear searching for food entering
a Westy occupied by people. I've spent several weeks a year for the past
several years camping in a VW in bear country in the US and Canada and
haven't seen it yet.  So I don't think you have to worry too much about
sleeping in your Westy with your food in the cabinets and fridge.

Bears entering an unoccupied vehicle for food is a different story- this
happens all the time, with Westys or any other vehicle.  Years ago in
Yosemite I had a bear tear the interior of my unoccupied car to shreds to
get at food in the trunk. ( For some reason Yosemite is and always has been
one of the worst places for bears breaking into cars, much worse than
Yellowstone, Alaska, Canada, or other well-known bear habitat.)  And I've
dashed out of a tent more than once to chase away a bear trying to get into
an unoccupied car nearby.  But I think for the most part bears will choose
targets other than occupied vehicles.  

Your best bet in places where bears are numerous is to keep food out of
sight- don't leave food containers or coolers where they can be seen by a
bear looking in.  Keep the vehicle and your camp as clean as possible and
avoid really odiferous food such as bacon.  I think if the inside of your
vehicle is uncluttered looking without piles of bags and boxes(hard to do
on long trips) they are less likely to try to break in.

And make sure your comprehensive insurance is paid up.

Bill
www.geocities.com/yosemite/gorge/1706