The Alabama connection needs more work, and I have starting on that project. Here's what I've found so far.
Guy Johnson's "Cruzee/Cursey" Tunnel in Alabama, which he nor anyone else has located until now, is really the Coosa Tunnel, which was constructed 1886-88 by Columbus and Western Railway line, who were completing the rail connection between Columbus, GA, and Birmingham, AL. Note how close "C&W" is to "C&O." Some of Johnson's informants mentioned Oak Mountain Tunnel, which is on the same line just north (2 miles?) of the Coosa Mountain Tunnel, just as they said. These locations are east and a bit south of Birmingham.
Red Mountain, also mentioned by these informants, is nearby, too. It is just east of Birmingham, and I suspect that the C&W might have tunneled there, too, although I haven't confirmed this yet.
The Blankenship broadside was recovered in the mid-1920s from a woman living in Rome, GA. According to a white pages search, there are 26 Blankenships now living in Rome (with telephones). I don't yet know whether or not any of these are related to W. T. Blankenship, who produced the broadside of John Henry. Rome is less than 100 miles northeast of Coosa and Oak Mountain Tunnels.
One of the Alabama informants claimed that there was a crowd of about 500 standing around watching the competition. If that were so, then I believe that it would have been covered in local newspapers. I intend to launch a search soon of Birmingham and vicinity newspapers (and Rome newspapers).
As for Big Bend Tunnel in WV, I think it significant that that intensive searches for John Henry there failed. Those who still favor that location have to ignore a tremendous number of negative reports and inconsistencies among the second/third/fourth-hand positive ones. I think that the Big Bend possibility has been dead ever since the investigations of Johnson and Louis Chappell.
Alabama hasn't failed, at least yet, so I think that it should be considered the favorite possibility at this time.
John Garst firstname.lastname@example.org