The ledge on the quarry is deliberate, it's not hard to get to at all and is an obvious pathway. Shit the Deathclaws have pathing to try and hide from you while you are up there. You just waste a shit tonne of ammo doing it early on with low skills. If they didn't want you doing that it'd be like the outter quarry wall or the wall behind Boulder Town etc. Or the massively high quest speech checks.
Deathclaws and Nightkin just need a good leg crippling and it's over. There are plenty of explosives in the game hmm can you still make the dart gun? I'm guessing no, that made Deathclaws a non-issue.
FYI I got bored of shooting while lvl8 or something reloaded and went elsewhere.