As a side note, if carrying, you must notify the occupant and ask permission to enter a private residence (this can be entertaining).
this is only the case when they have a sign, right? I understood the business part you mentioned just before my above quote, but I am getting at the private home bit. It isn't an issue where I live(I must leave if informed to), but I didn't think there was a law for what you mentioned in the quote above.
Lastly, I think you are correct about respecting the laws of military installations. One would be ill-advised to think it would be ok to skirt that law if they don't have a legal reason. There access laws can change frequently depending on what level of threat the country is on too(like whether a license is enough to get on with a vehicle sticker), but the firearm bit is pretty solid.