There is no reason you can't drive with the fridge on propane.  The only
hazard is that if you park the van on a hill for any length of time you
run the risk of ruining the fridge, it must be within a few degrees of
level or the liquids inside can't trickle down to the reservoir that is
heated by the flame, and you "cook" the system.  See
http://www.rvmobile.com/TECH/TROUBLE/COOLDOC.HTM for a discussion of
this.

The 12v operation lets you conserve propane (but it may be cheaper to
burn gasoline to run the alternator than to use propane, the list's
electronics experts can tell us this), and some folks have trouble
keeping the flame lit while driving, but I've never had this problem.

--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)

Personal mechanic for:
'70 MGB GT (Daughter's)

Assisting on Restoration (and spending OPM):
'72 MGB GT (Was daughter's, now son's)
'64 MGB (Son's)

Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT