Choctaw casino in Durant, Oklahoma has it's own KOA campground. But, they will also let you boondock at the casino. Security said it was fine for a night or two. We initially parked up front near the highway. But we then moved more to the rear, ending up in the "C" lot. Much quieter, but there was a train or two throughout the night. Security is always patrolling the lots. Felt very safe. Sign up for the players club card and you'll get $10 of free play.