Strictly speaking, laws apply everywhere unless there is an exception set down in the statute itself. Now, some state laws have specific exceptions for people engaged in fishing/camping/hunting and may or may not make mention of having a valid hunting or fishing license.
One thing worth noting is that while doing outdoors activities, concealment is less of an issue if the state law only covers carrying concealed and no openly. You can open carry without many worries while hiking or hunting, whereas open carry in a 7-11 might get a worried call to the police even if technically legal. For example over hear in Maryland, our laws on blades are strictly related to concealment. Out on the trail you can carry a machete if you want so long as it's carried openly.
In Tennessee, the "4 inch law," § 39-17-1307, contains the following defenses, enumerated under § 39-17-1308:
(a) It is a defense to the application of § 39-17-1307 if the possession or carrying was:
...
(3) At the person's:
(A) Place of residence;
(B) Place of business; or
(C) Premises;
(4) Incident to lawful hunting, trapping, fishing, camping, sport shooting or other lawful activity;
(5) By a person possessing a rifle or shotgun while engaged in the lawful protection of livestock from predatory animals;
...
(9) By any person possessing a club or baton who holds a certificate that the person has had training in the use of a club or baton for self-defense that is valid and issued by a certified person authorized to give training in the use of clubs or batons, and is not prohibited from purchasing a firearm under any local, state or federal laws;
Full Statute Here
So it would appear TN has a camping exception to the law.
Now for National Parks, several sources I have consulted claim that the parks are considered federal property. While this makes them partially exempt from some state laws, it subjects them to the highly restrictive Federal property weapon law (
http://www4.law.cornell.edu/uscode/html/uscode18/usc_sec_18_00000930----000-.html). This limits all blades to 2.5" or less, and even bear spray is illegal. At least, that is what many rangers on these parks
claim. I say that because if you read the statute, it technically only applies to buildings. In truth I have gotten different versions of this story and to my knowledge, the issue hasn't been challenged in court yet.
