I do the drive every few weeks and we are lucky in that even though Tesla has not addressed the issue yet we do have new options. McAlester is about half way and there is a
Francis Solar DC fast charger downtown there at the headquarters of Rover.Taxi. They have the CHAdeMO adapters needed on site so you don't need to buy the adapter if you don't want to. I usually get there with 30-40% of charge and can get up 80%-90% in less than an hour and under $14. They also have a lounge there if want to go inside. There are other Francis Solar DC fast chargers popping up all over Oklahoma so those are other options if you aren't leaving with at least a 70% charge and can't make it to McAlester.
There are Tesla Superchargers planned in Denison and in Fort Smith but since those aren't close to the middle of the trip, they aren't going to be as good of choice as McAlester IMO.