Try the nest in the south east across the river, its unmarked but you've got a good dozen deathclaws, a alpha and a matriarch. Good luck sneaking up on them.
Sounds good, there should be an anti-materiel rifle sold by the gun runners or by the brotherhood of steel quartermaster. this is a good time to have 100 in guns and 10 in strength...
Sure, a weapon that allows you to never be detected? Piece of cake, but try anything else? Good luck. Although I did successfully kill a deathclaw at Level 8 by skillfully jumping onto a ledge they couldn't reach, I had 5 deathclaws around me, and me armed with a 9mm submachine gun.
But now, at level 25, i just put 2 rounds of .50MG into their skulls, or 1 round of .50 Incendiary. This is at Norman difficulty.
Actually, i USUALLY get detected. the suppressor is only for the purpose of having just a few more seconds before being detected, perhaps gaining another sneak critical. otherwise i wouldn't take the suppressor. it makes the weapon too silent. that is bad if you like noisy weapons.