Spending time (maybe too much time) researching the Russian Revolution and, in particular, the retreat of the White Army in Siberia. Why? For a future Wilk novel (probably the first, chronologically) that I am unlikely to write anytime soon. That's okay, the ideas I pick up now will work away in my head until I am ready to tackle the writing. I've already realized that the basic scenario I had worked out, Wilk passing through Siberia to China, is not going to be as smooth as I had envisioned, at least not if I set it in summer of 1919! But that may add more interest and adventure to the whole thing.
I am also looking into the aircraft involved, as Wilk was a pilot who served with Germany in WW1 (coming from the German-ruled part of Poland) and then with the Reds in the immediate post-war period. My first thought was that he would accompany a couple airplanes to China via railway but I see now that the lines through Siberia were still White-controlled during that time-frame. So he will have to fly at least part of the way, perhaps through the Turkestan area. All that will be worked out eventually and we can get to the main adventure...China!