I just noticed that the next issue of ATO magazine ("Guns of the Askari," which looks pretty interesting) posted their table of contents, which includes an article about this Morgan game and some variant rules.
I haven't seen anyone mention the game in awhile and wondered if the postcards might be out of print...but just found out from the publisher that they are including one in each issue of the game.
So if you've been reading these threads thinking, "that sounds cool," here is an easy way to get the game, and an article about the campaign, and some additional rules.
Here is the listing for the game
But you can see the ToC at their FB page.
BUT NOTE-- Just read that the copies going into the issue are the LAST copies of this game. So after the issue ships, Morgan's a Comin'! will be oop.
No, all copies of ATO #38 contain the last copies of "Morgan's a' Comin'!" inside (as a bonus). Subscribers also get the new "The Union Forever" Pocket Battle Game and that missing chart from "For Bloody Honor."