Each person must have a permit for all entry into the Barry Goldwater Military Range and into Cabeza Prieta Wildlife Refuge. It is one permit but you must call the appropriate officials before entering the different areas. Permits have to be picked up in person for the BGMR. For the western area, get the permit at the main gate for Yuma Marine Corp Air Station between 9am and 3pm weekdays. For the eastern area, search online for the BGMR to find out where and when to pick up the permit. Permits are all good until July of each year.
We were checked by the Border Patrol repeatedly during this trip but they were always friendly.