Fallout 76

• You cannot really lock yourself out of anything.

• A possible exception is one of the main quests, "The Elusive Crane". When Dutchess asks you to wake up Crane, make sure not to accidentally kill him, or you won't get the keycard for the Gauley Mine Roboco entrance.

• Pistols are not really supported as a realistic option beyond the early game due to a lack of empowering abilities.