Ditto on TWN's rare but this time profound wisdom.
January is likely to be cold and tough in Northern Nevada ..Southern Nevada (the girlie end of the state) is likely to be pretty pleasant, but the good riding is more limited on that end of the state.
Both Nevada and CA have wonderful winter riding ...but the problem is that getting to where you want to go can be trouble and no surprise the best riding is in places with Dicey weather.
here is some advice free to you this time:
Death Valley is wonderful in January. Great weather, no people and all is good. You can access it from many locations and leave it in another location. I frequent DV in the winter, it is a real treat.