The battle fields around my area are mostly private property and most land owners are hesitant to let people go mding anymore.
I luckily know some of the owners by family connections or friends and that goes a long ways towards getting permission.
I seem to be able to get on property close to the battles but not the main battlefields.
I wonder if the main fields might be less productive than the outer fringes because of being hunted hard in the past.