Paul,

For winter driving, the best solution I found when I had a 2WD van was a pair
of Nokian Hakkapeliita's with a couple of hundred pounds of ballast over the
rear wheels.  For ballast I would use what the local masonry supply yard
called "anti-skid" which was sharp-edged, broken stone the size of peas.  They kept
recycled paper flour sacks from a bakery on hand just for that purpose and a
hundredweight of the anti-skid was about half a bag.  The handy-dandy thing
about the anti-skid is that there is nothing better to use for traction if you
get hung up and it is in arms reach when you really need it.

George