Much of the snow wheeling that I have done, has been on the same trails that get run in the no snow months, so the same challenges are there. I have found that with increased air pressures, that things are far more difficult to get past, even in the snow.
Good luck!
-Steve
Good assumtion romer...
I run lower air pressure off road all the time, rocks, mud, snow, sand, heavy/loamy dirts, anything. It helps more that you would think.
I have this set of deflators, extra-low kit on the bottom...
http://www.oasisoffroad.com/tireInflatorDeflator.html
Seem to work...