The guide to the markers at Honey Springs includes excerpts from a ton of eyewitness accounts of the battle. You should be able to obtain it from the park. Also you might take a look at the book "The Prairie was on Fire." It includes eyewitness accounts of a number of battles, including the Honey Springs/Elk Creek fight.
If they are of interest to you, I also have collected a few letters written to newspapers by officers and soldiers who fought at Honey Springs.