Hm, well I took a look. It makes no sense for there to be Wyoming dialect in a story about Pittsburgh.
Writing in American dialects is a bit of an effort in futility. Part of the problem is the commonality of certain structures, but also because of cultural references.
The structural part has to do with stuff like the finite ways English has to indicate variations in vowel sounds. Another thing is that contractions, truncations, mispronunciations, and word order are also shared by multiple American regionalisms. "I'm gittin' it" could be used to spell a statement by a man or woman from Brooklyn, Atlanta, St. Louis, Riverton, or San Francisco.
Cultural reference comes into play to tell us which sounds are likely to go with those words. If you know the character is an urban black, you'll hear "I'm gittin' it" in your head one way. If you know the character is from a ranch in Wyoming, you'll hear it different.
I don't see testadura writing writing her dialogue in a Wyoming dialect. i her writing in dialect period. Knowing that Ennis & family moved up from 40 miles south of Pittsburgh, I expect them to have something closer to a West Virginia accent. Remember that geographically, southwest Pennsylvania is cradled by the "finger" and "thumb" of West Virginia. I've visited Waynesburg, PA. There's plenty of West Virginian accents of varying thickness in that town. So I hear West Virginia when I read the dialogue.