Almost everything you said is correct, but you forgot that a militia is not a military organization, they are paramilitary and are still civilians. Legal definition of a militia does not mention requirements of age or health. National Guard is a military organization that is funded by public tax dollars and mandates specific ages and health.

Because of this fact, militia are only mandated by the US Constitution to be “well regulated” so that when a state governor calls them to action, they need to form and follow a chain-of-command, which requires the ability to train with their firearms on their own personal time and their own dime (they are legally not allowed to be a burden to the taxpayers in any way, unlike the state National Guard).

So this means unrestricted access to commercial firearms and the freedom to train on federal land or private property with their own personally owned (not government issue) weapons.