I'm reading this right after shoveling about 2-3 inches of the white stuff off my driveway and while watching more fall on the driveway again. What timing.
How long do your roads and trails stay snow covered and slippery? Typically, around here, a snowstorm will result in maybe 2-3 days of bad conditions and then the surfaces are pretty good in most places. If this is the case, the rule is adjustment. Just stick with easy running during this time. Save your workouts for when you have clear surfaces to run on again. If not, do you have indoor options? I usually don't hit a treadmill until all other alternatives are exhausted but, if it comes to that, treadmills can be an alternative. Another option would be indoor tracks. You could check with local colleges to see if they have an indoor track that the public can use.
As for running on the slippery surfaces, it sounds like you have the drill down. Another thing you can try is the screw shoe if you simply need more traction.