By the way, I'm wondering if everyone caught the play on words (I didn't get it right away either):
"SOONER Dead" is set in Gamma Oklahoma (where the author is from, btw) and the Sooners are the Oklahoma University's mascot.
A bit corny, I know, but still pretty clever.
Yeah, but the original Sooners were settlers who resied in Indian Territory (either legally or illegally) prior to opening of the lands for white settlement.
Note the following taken from wikipedia (not a definitive source by any stretch of the imagination but it does correlate to most material I've read and dimly recall from taking courses in Oklahoma history):
Sooners is the name given to settlers in the midwest of the United States who entered the Unassigned Lands in what is now the state of Oklahoma before President Grover Cleveland officially proclaimed them open to settlement on March 2, 1889 with the Indian Appropriations Act of 1889. The name derived from the "sooner clause" of the Act, which stated that anyone who entered and occupied the land prior to the opening time would be denied the right to claim land.[1]
Sooners were often deputy marshals, land surveyors, railroad employees, and others who were able to legally enter the territory early.[2] Some Sooners crossed into the territory illegally at night, and were originally called "moonshiners" because they entered "by the light of the moon." These Sooners would hide in ditches at night and suddenly appear to stake their claim after the land run started, hours ahead of legal settlers.[1]
The term Boomer relating to Oklahoma refers to participants in the "Boomer Movement," white settlers who believed the Unassigned Lands were public property and open to anyone for settlement, not just Indian tribes. Their reasoning came from a clause in the Homestead Act of 1862, which said that any settler could claim 160 acres (0.65 km2) of public land.[3] Some Boomers entered and were removed more than once by the United States Army.[4]
Those who actually observed the official start of the land run and began the race for free land often found choice sections of land already occupied by Sooners or, in some cases, by Boomers. Problems with Sooners continued with each successive land run; in an 1895 land run as much as half of the available land was taken by Sooners. Litigation between legitimate land-run participants and Sooners continued well into the 20th century, and eventually the United States Department of the Interior was given ultimate authority to settle the disputes.[1]
In 1908, the University of Oklahoma adopted "Sooners" as the nickname of their football team, after having first tried "Rough Riders" and "Boomers". Eventually, Oklahoma became known as "The Sooner State."
As for the novel itself, I interpret it as one of those alternate Earths that was affected by the Big Mistake, not the one described in the Gamma World big box.
Aside from the reference to the mountains having gotten bigger due to tectonic shifting in California, it isn't the Oklahoma I'm setting up for my Gamma World campaign. 
visit my blog about writing, voice-over,and games (and not necessarily in that order) at mdarinyoung.wordpress.com
