This summer I crossed the Tibetan Plateau in Qinghai, entering from Xinjiang, through Golmud, Yushu and exiting in Sichuan.
If you are interested in this route, be aware that South from Golmud (30-35km) there's a police checkpoint. Even if you are allowed to travel in Qinghai, since that road leads to Lhasa, the police can stop and not let you pass, even if you explain that you are heading to Yushu. There are reports of people that had to come back to Golmud as well as lucky guys who were able to convince the police.
If you don't feel so lucky and want to take a police-free route, there is another option that you can't see on google maps or OSM, and is more ore less the same length.
Instead of going South, from Golmud take East along the road to Xining (G109). After around 300km you will reach a town called Xiangride. It is before Dulan. There is an highway under constructions that from here passes the mountains (4400m) and then takes you to the G214 to Yushu, near the Donggei Cuona Lake. The junction in Xiangride wasn't finished yet in August 2015, so it's not so easy to find it, but you can ask local people. Just do not follow the old brown signs to Gouli, because it is the old, narrow, unpaved road. Anyway, coming from Golmud, the junction is just few hundreds meters before the bridge on the river.
The highway is perfectly paved except 4-5 km on top (as August 2015), but still in good conditions. It's about 150km to reach the G214, and there are no towns in the middle, only few houses. Almost no traffic at all.
Hope it may help you,