Drive really slow when starting from stops and avoid big hills, and get rear ties with studs. Weight in the bed won't do ****. I had 400 lbs in my Ranger an it didn't help do anything but increase stopping distance and lower gas mileage. Go the right way, get a cheap beater 4x4 truck and use it only when it's impossible to drive the Ranger.
...just as a side note, I live in the U.P. of Michigan and we get around 250"-300" of snow per year. I see many 2wd vehicles getting around fine, it's all in the driver. The only reason I have 4wd is in case I truly need it, I engaged 4x4 once this winter.
1997 Chevy Blazer, 4.3 v6, 156k miles