Here is from the SBNF:
Siberia Creek Trail 1W04
It is 6.8 miles to Bear Creek. The trail is rated strenuous when passable. However, in recent years including the 2015 season, the trail is only maintained 1.5 miles to “Gunsight” and rated easy.
Unfortunately approximately .8mi past Gunsight the trail is overgrown with heavy brush fields making it impossible to reach Bear Creek by this route.
I have seen that area from the road 1N64 near Seven Pines area and it is very thick over there. So make sure you bring your suit of armor. And beware of Rattle Snakes specially near Bear Creek area where I have seen a couple.