As of this afternoon, 5-25-17, the Back Road is now open in Plumas County, though the Road Department reports several areas of narrow roadway, requiring you to be alert.
Word from the Forest Service is that the French Creek detour around Mountain House is functional, though designed primarily for logging trucks, and they are not encouraging tourist or vacationing traffic. But, neither can they keep you off of it. So just be careful when driving it. It is reported to be newly graded gravel in most parts, about 3 miles long.
Big Creek road is also open as of Wednesday afternoon.