Your trip plan overlaps quite a bit with what Motokai and I did last July. Both of us were on JH600. Our jialings performed amicably without breaking a sweat on highly varied road conditions in that part of the country, including expressways. The trip lasted over 5000 km in 17 days. The Jialing has more than proven itself.
The link:
http://www.mychinamoto.com/forums/sh...sha-to-Ürümqi)
By the way, you don't want to miss Qilianshan right along the Gansu and Qinghai boarder for your trip.