The shortest route to reach US mainland from China is to take off from Heilongjiang, fly over the Russian Far East, skirt south of the Kamchatka Peninsula, Aleutian Islands, then reach the US West Coast. Assuming we are doing a peace time patrol and avoids entering other country's air space except Russia, this route measures about 75,00 km one way and 15,000 km round trip. This is not much further than the combat range of the Tu-160 and totally doable with air refueling.
Alternatively, if we choose a Pacific route without entering Russian airspace, Japan will be in the way making the jounery much longer. We have to fly through the Miyako Strait and Izu Islands, two choke points heavily monitored by radar, before reaching Calfornia. The distance is about 20,000 km round trip which, IMHO, is beyond the reach of PLA's current technologies.
