Historically, from the end of the Civil war until early 1880s the United States continued to remove the eastern Indian Tribes from land attractive to whites. Scores of native people were forced to leave their homes and move to Oklahoma. The era of Indian Settlement lasted from 1820 until 1880. White settlements technically began in 1889 and ended in 1906.
White settlers were forbidden to live in Indian Territory, except with permission from the resident Tribe, however, thousands of intruders streamed into the territory much earlier than 1889, right after the Civil War. The Arnetts were probably some of the early intruders.
The range cattle industry started in 1870 & 1880. The herds were driven through Oklahoma to Kansas along Kansas Pacific & Texas R. R. route, the Chisholm Trail etc. Later on the railroad.
The Arnetts could have been cattle men and followed some of the drives, but I think it is more likely that Annie's father worked on the railroad. Annie' description of where she lived compared with the history of the railroads in Oklahoma shows a good fit, I think it is possible their father, John worked for the railroad. He may have worked for The Kansas Pacific & Texas RR.
One of the first R.R. in Indian Territory was the Kansas Pacific & Texas RR. (The Katy) It started in Kansas and first reached Indian Territory June 6, 1870. By the spring of 1872 it had crossed the North fork of the Canadian River into the Cherokee Nation and reached McAlester by mid-summer. March 8, 1873 it was declared complete. The Katy tracks were connected to the Houston & Texas Central Railroad at Denison Texas. [My grandmother Annie was born in Denison Texas in 1874.]
The Katy followed the route known as the Texas Road which was more than 50 years old. The road went through Checotah. The Atlantic Pacific Railroad surveyed an East-West path through Indian Territory as early as 1855. It met With the Southern Pacific to make a transcontinental hook up near El Paso, Texas in 1881. In 1881 Annie would have been seven years old, old enough to remember living in El Paso for a while before they moved to Porum, OK. This could account for his children telling the census taker they were born in Indian Territory, also how Annie remembered Denison and El Paso, Texas.
Whatever Annie's father's first name, he may have gone to Texas or Arkansas from Georgia before the war. Then settled in Arkansas, Missouri or Kansas. Fought in the Civil War from 1862 to 1866. Moved around a while, or followed the R.R. to settle in Indian Territory, sometime in the 1870 to 1880s. Assuming Will Samuel is the first child of our Arnett, he was born in Arkansas in 1856 or 1857. This was before the Civil War.
While the Arnetts were herding cattle or working on the railroad, about 1880 two additional Indian families, the Keiths and the McClures, moved into the Cherokee Nation. Both families later became important to the Arnett family. See footnote(1) Chapter VI for description of early Checotah