After checking through some census records, I have found that Burleigh's father did not die "when he was a lad", as his write up in "Spitballers" said. Charles Clark told me that his dad would send Burleigh slippery elm bark from Wisconsin when he was playing in the majors, and I believe him. The census shows he was still alive in 1920, which was several years after Burleigh made his major league debut. I don't blame the authors of the "Spitballers" book at all, as it was a minute detail overlooked in what is otherwise an incredibly great read.
Thus, I left some stuff in the article that Charles had told me. I also included a blurb about Happy Felsch, who played shortstop in the only exhibition game Eau Claire had in 1912. He failed to make the team (and interestingly enough, Burleigh didn't play and still made his pro debut with the team a few days later--playing shortstop). Yet, Felsch's obituary in the Sporting News referenced the "brief trial" in Eau Claire, so it must have had some sort of impact on him.
The article is with SABR now, and hopefully I'll learn the fate of it relatively soon.