If you are coming from Arizona to Northern California, this is the route to take. I like it much better than the 10 through the Inland Empire.
CalTrans says that the road is closed to westbound traffic between Mojave and Tehachapi for construction until the end of the year. I don't know what the detour is like, but it can't be too bad since this is a well travelled road.
Regarding the CHP comment above, remember that the towing speed limit in California is 55 mph everywhere.