Ahhhhh! You've found my homeland. The best time to go is between Oct through May.
The rest of the months are too hot. If you like big crowds then go on any of the holiday weekends. The sand gets pretty beat up during these weekends. For a quieter time I suggest a non-holiday weekend.
For all the do's and don't's including maps, tips, GPS, etc. go to the official site at
http://www.[censored]/
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