Cold weather campers...About a year or so ago there was a discussion of
heaters on the list.  Many folks have successfully used the Plat Cat VENTED
catalytic heater, by Thermal Systems, out of Washington (I believe Olympia).
We bought one, and it's great.  They make 2 sizes, we got the larger one.
It mounts to 2 bolts placed behind the passenger seat,and is fueled via  T
off the system and flexible hose.  It removes easilyin the summer, and heats
well in the winter (for skiing).

The advantage of this heater over the Olympian is that it's vented, and you
don't have to open any windows or vents.  We felt safer ('tho I expect our
vans are drafty enough that a non-vented heater may be safe).  The other
advantage is that it has a thermostat, which in our case is mounted on the
pillar behind the driver.

It may be a bit more $$ than the Olympian, and harder to find (The company
is very good about ordering directly, their service is great).

We're very happy with the heater.

John
'90 Syncro Westfalia--Vic
SLC, UT