Suggest winterforce, they are pretty good year round and aggressive enough. Heck it is near impossible to get a BRAT stuck on All seasons, they are pretty tough to get stuck on any tire, especially with a rear lsd. winterforce in 175/70/13 work fine.
only 71 each now
http://www.tirerack.com/tires/tires....omCompare1=yes
Even offroading a BRAT, you don't need a mud tire, they are that good.