Pike originally wanted to hold Ft Davis on the south side of the Arkansas, believing that McCulloch would be in AR and Price in MO protecting his right flank. He expected an invasion from Kansas down the Texas Road.
After the defeat at Pea Ridge, Pike expected Van Dorn to fall back to the Van Buren, Ft Smith, Frog Bayou area. With the Boston Mountains undefended, Pike couldn't hold Ft Davis so he was going to fall back to Scalesville which I beleive is north of present McAlester closer to the Canadian... north of Perryville... but uncertain right now. I think it was where Marcy's Route (California Trail) crosses the Texas Road which is north of the Ft Smith to Ft Arbuckle Road.
When Van Dorn abandoned western Arkansas, Pike saw that a relatively small Union force could flank and surround him via Ft Smith so he fell back further. Pike told Watie if they were north of the Canadian at Starr's Settlement they would be like a "rat in a trap". Starr's Settlement is the home/ranch of Thomas Starr just south and west of Briartown on the north side of the Canadian and in the Cherokee Nation. [There is a reference in the ORs to "Stan's Place" which I have little doubt is a mistranscription of "Starr's Place"]
Pike says he wants a location south of the junction of the Texas Road and the Ft Smith-Boggy Depot Road. This junction was near present Stringtown OK just a few miles north of Atoka. At the point of the junction, three of the Boggies -- Little Boggy, Middle/Muddy Boggy, and Clear/South Boggy -- were still in his rear. Somewhere in the middle of the three, he could perhaps use them to protect from attack from the east or west -- not just from the north -- but with the Boggies to his south he could still be trapped during high water.
Obviously Pike changed his mind and chose the crossing of the Blue at Nail's Bridge for the location of Ft McCulloch. The Atoka/Stringtown area was a common defensive position for the Confederates throughout the war. Dawson's 19th Ark Inf must have been there for a while as there are several of the regiment buried in the Confederate Cemetery north of Atoka. It is where Steele was going to make his stand to stop Blunt's invasion when Perryville was burned. [Blunt of course turned and marched to Ft Smith instead].