Call The Sequoyah Lodge at (918) 772-2545 and tell them you are booking for the Big Om Yoga Retreat. ($100/night for a room that holds 2-6 people, two night minimum) You must book before May 27th, limited lodging available.
You want to camp or park your RV? Go to https://www.gocampok.com/, click "Search State parks", enter the dates you will be staying (June 17th-19th), and click the "S", Sequahya State Park is at the top of the list. The Choctaw camp site is closest to The Lodge, it is near the Nature Center, and also has the swim beach. RV spots are ~$32.00 per night. Camping is about ~$18 per night and is on a first come first serve basis. This park is very large and it is highly unlikely that camping spots will fill up.