We've stayed at the O/N area, and at the camp ground. Both worked. The O/N area can get very full, they moved us up to one of the parking lots, off on the south side of the casino. Quiet place to catch some sleep. I also noted that 7Feathers wasn't the best buy for fuel.
The restaurant had an excellent ten dollar steak dinner, but you had to ask for it as it wasn't on the menu.
Good luck....
If you receive help from other members, don't forget to update your topic with the results.