While Watie and Gano did meet at Camp Pike or Fort McCulloch on September 13, 1864, as far as I know Watie's headquarters, i.e. that of the First Indian Brigade, prior to the Cabin Creek raid was at Camp Corser, Choctaw Nation (per Watie's after action report of the Cabin Creek raid in the OR). It is quite possible that Watie used it as headquarters in 1865, however, although I hadn't noticed that fact before.