A good way to start is to survey the California Sno-Park places. Then, on a topo map, study the unplowed jeep roads that leave from those places. In some cases, there are Sno-Park places that are launching sites for snowmobiles. Sometimes you figure out where the snowmobiles are going, and then you snowshoe the other direction.
When I think of those Sno-Parks, I think of the cross country ski routes that I have covered from there.
Try Carson Pass for openers. I can think of four ski routes from there.