How to go about getting the player character to 'Snowboard'/slide down a hill

Try creating a physical material class in the CB. I have no idea if this is what you need, but physical materials govern the physics properties of surfaces, and are assigned at a material level; allowing you to have a snow material, and a snow physics definition that is automatically used when you are in contact with a surface using your snow material.

TL;DR: Physical Materials should allow you to set the slipperiness of a surface.