That opening scene is factual, based on the available evidence, and on common sense.
Remember that the first sentences of that excerpt from Part One, in which I describe Phillip walking to Langworthy’s shop? Here’s what I knew: The Best family had almost no money at the time. They’d recently emigrated, and put all of their cash into the piece of property they bought. So it’s unlikely they used a horse to get around Milwaukee. Horses were (and are) expensive, and regular folks relied on their feet to get from one place to another. Moreover, in 1844, there wasn’t any public transportation in town.
So it’s safe to assume that Phillip walked to Langworthy's shop. But I could also assume that he walked because of the short distance between his house and Langworthy’s shop.
How do I know that? I found one of Langworthy’s advertisements in the newspaper, and it included his address. Next, I found a map of Milwaukee that dated to the period. If I remember right, the one I used was produced around 1850 or 1852 (I’m too lazy to rummage through my files to find it right now to find the map), which was close enough to 1844 to give me a visual image of the town’s streets at the time of Phillip’s trek.
Then I used a current map of Milwaukee to calculate the distance from the Best’s brewery to the shop. I also walked the path myself when I visited Milwaukee to do research. It’s not far -- a half mile or so?
But what lay in between the two points? What did Phillip see as he walked from his house to the riverfront and Langworthy’s shop? How do I know about the millrace, the docks, the tanneries, and so forth?
I determined that by reading eyewitness descriptions of the town as it appeared in 1844: Letters written during the 1840s, diaries, newspapers, government documents. Once I’d done all of that, I was able to construct a mental image of Phillip making his way along the crowded sidewalks to Langworthy’s shop. But that image was based on multiple, verifiable facts. Reliable facts.
Next time: How do I decide which sources are reliable?