If your a early level AVOID THEM but when you get one just use Anti-Material Rifle.I like to use Mercy with brotherhood or enclave powerarmor Im level 34 trying to get to NCR Ranger Safehouse, i should use Anti-Material Rifles? and i cant use Power Armor...? Just fast travel to REPCONN HQ and head there, you'll find no deathclaws.
I found using Tri-Beam Lasers work really well and if you have one and want to spare a couple; you can never go wrong with the Fat Man.
Watch out for the Fat Man, as you can hit yourself pretty easily in the rocky area that surrounds the NCR Not-So-Safehouse, but if too close or under atack by Deathclaws you would have some trouble going for the Anti-Material Rifle, so give the Brush Gun a squeeze and you'll find it pretty fun to hunt Deathclaws. As for the armor, I don't any counter-recommendations about Power Armors, but I always go for something lighter, like the Desert Ranger Combat Armor, if you have Honest Hearts like I do, or the NCR Ranger Combat Armor if you don't. If you ain't got money to buy tha Brush Gun or the A-M Rifle, try searching for the YCS/186, northwest of the Strip, but if you have Wild Wasteland the gun will be cut from the game, and replaced buy the Alien Blaster, so you should head to Vault 22 and get the AER14-Prototype and try out a few Maximum MF's.
Also don´t forget to use chems like Slasher, Psycho or Yao Guai meat (Honest Hearts only).