Yeah that's why this study to me is the most important one done to date:

We collected real-time travel data during the epidemic using the Baidu® Migration server (Fig. 2A and Table S2). The server an online platform summarizing mobile phone travel data through Baidu® Huiyan [https://huiyan.baidu.com/]. Baidu® Huiyan is a widely used positioning system in China. It processes >120 billion positioning requests daily through GPS, WIFI and other means [https://huiyan.baidu.com/]. Therefore, the data represents a reliable, real-time and high-resolution source of travelpatterns in China. We extracted daily travel datafromWuhan to each of the provinces. We found that in general, between 40,000 to 140,000peoplein Wuhan traveled to destinationsoutside of Hubei provincedaily beforethelock-down of the city on January 23, with travel peaks on January 9, 21 and 22 (Fig. 2B).Thus, it is likely that this massive flow of people from Hubei provinceduring January facilitated the rapid dissemination of virus.

In short, LANL modeled the disease outbreak using cell phone GPS data and got a much higher number than anyone else is using. Notably, China is using cell phone GPS data to enforce quarantine.

As far as where she contracted it,

"About 200 members of the Shincheonji Church of Jesus met at the epicenter of the coronavirus outbreak and mostly ignored rumors of the illness that began to swirl as early as November, a kindergarten teacher told the South China Morning Post."