The 1880 census has him born in Alabama The 1900 census has him and Miriam in OK and him born in AR Per that census he was married to Miriam for 24 years - since it was taken before Aug that would be the correct number of years for him and 'Masha' so you can figure they did not how to spell her name in either place but it was the same wife Do you know what happened to the other sons? I could not locate them in 1910 unless they went by middle names Do you know where George died? Do you know where the wife died?
Also have not had really anytime to try to hunt down Mire Misshe Brown - will have to figure out what her name was on earlier census
If may sound idiotic but in order to track down George's parents you really need to find other siblings in order to verify his family
As far as venturing into Texas - there was a land boom about that time - then later they opened the 'Indian" land in Oklahoma - or pretty much the whites went up and stole it so that would account for them venturing into the other states.