I've traveled from one end of China to the other and am likely the only author who has been to both the very southernmost tip (Sanya, Hainan Province) and the very northermost (Beiji Cun, Heilongjiang) facing the Amur River separating Russia and China. I've also stood on the banks of the Yalu River not 5m from North Korea, and travelled to the India borders in the west.
Most of my work for the guide over the past 4 editions has been covering these more remote provinces: Hainan, Qinghai, Xinjiang, Gansu, and the three northern provinces that comprises the former Manchuria, now Dongbei (Heilongjiang, Jilin and Changchun).
Researching and writing on China is a workout as destinations get ruined fast by overdevelopment, and as often by overzealous regulations that disallow private exploration, while previously unknown sites or regions open up just as quickly. I've added entire towns to the guide, in addition to many smaller sights, and in the case of Hainan, mapped out for the first time a round-the-island cycling tour (which I completed twice). That route became a new Top 30 Experience for China.
Relevant topics change rapidly, too. While pollution is a recurrent theme (I arrived in Dalian in 2010 just days after China's largest oil spill and wrote about that), in 2012 the story was the massive expansion in wind and solar capacity. Over the years, I've covered the growing economic ties between North Korea and China, unrest in Xinjiang, and skiing in Dongbei (which faded out as quickly as it came in).