Regarding cell towers. I checked the ATT wireless website and for that company, it looks like they had a tower in Weleetka. Great coverage extends around the town for about 2-3 miles, as does great coverage on either side of I-40. There's a pocket between Weleetka and I-40 where coverage is mediocre, so I guess cell's there can get either the Weleetka one or one along I-40.
If they lived closer to Weleetka, I'd think the ping info on that would be easier to get and track for that time frame. However, one report I read said that Skyla was from Henryetta, which leads me to believe they lived closer to the NE of Weleetka and may be in the nether zone.
All this assuming is based on similar cell phone reception/tower placement among other cell providers. I realize that that is a wide assumption.