Minuteman Missile National Historic Site is governed by Codes of Federal Regulations (CFR) and the park superintendent can "model" these regulations to fit the park's special needs.
Not all parks have historical structures. Each park is unique and has its own unique set of laws, as well as the laws that apply to every unit, such as "littering" for instance. If the question you have in mind involves whether what you are doing is legal or not, then you can look in the Superintendent's Compendium to find your answer.
Click here for the 2014 Superintendent's Compendium (440 KB PDF)
These regulations apply in addition to the criminal laws of the United States and the regulations contained in Title 36 of the Code of Federal Regulations. A person convicted of violating any provision of these regulations shall be punished by a fine as provided by law, or by imprisonment not exceeding 6 months, or both, and shall be adjudged to pay all costs of the proceedings.