In the book "A Life Of Albert Pike by Walter Lee Brown" pages 401-402. Pikes first choice on moving south was to locate his headquarters at Scalesville, but before Quesenbury had begun work on the proposed headquarters at Scalesville, Pike received word that Van Dorn had decided to take confederate forces to the East side of Arkansas. Pike thinking his right flank will be exposed decides to move on down to the location of Fort McCulloch.

As for the route of the 19th.back to Ark.

William E Woodruff JR. Battery was sent back to Ark. at the same time. You might find info on this. The source Brown gives for Woodruff's Battery
is "With The Light Guns in 61-65, Reminiscences of Eleven Arkansas, Missouri and Texas Light Batteries, in the civil War. Little Rock Ark. ,1903

Elmer