Be sure to check on what days the park is closed. When I was there, it happened on two days every week, on days that were reserved for Air Force flyovers. We were there in the spring, and we were fortunate in that the normally "closed" days were cancelled for some reason, so we got into the park each day we were in the vicinity (including one sand storm, which was an exciting experience -- left lots of dust spots on my sensor, even though I never changed lenses. Didn't discover that until I got home a few weeks later.)