Buckner is undoubtedly speaking of the Battle of Round Mountain ("night battle on the Red Fork") and Chusto Talasah ("the recent engagement on Little Verdegris"). The Little Verdigris is now known as the Caney. Cooper moved to "Musgrove's on Caney" to meet Drew's Regt but found that Drew had gone on and camped on Bird Creek.
Buckner lived a Micco (North Fork Town) which is now under Lake Eufaula just northeast of present Eufala. He is writing from the Creek Agency which was northwest of Muskogee and nearly directly west of the 'Castle of Muskogee' at the base of Fern Mountain.
See map at
http://luna.library.okstate.edu:8180/luna/servlet/s/a2e7rv
Ken