What tactics are best for killing Deathclaws?
Solution 1:
Extreme range, sneak attack criticals, and armor-piercing bullets are your friends versus Deathclaws. If you're in possession of (and a decent shot with) a scoped hunting rifle or better sniper-type rifle, you can usually pick them off one at a time since they tend not to group up. If you're finding it impossible to get enough damage before they close the distance, you can always augment your plan by throwing down some mines on the path between you and the Deathclaw (make sure you back up some). Finally, it's handy to be able to quick switch to an automatic rifle to finish the job if the mines fail you.
Pulling Deathclaws one at a time like this is a slow and tedious process, but it works.
At the very least, you can always move on and come back later!
Solution 2:
Killing a death claw isn't easy and there is new easy way. There a few tricks to use when encountering deathclaws:
Use the Q35 rifle which I think is found in the robot factory. This rifle can be repaired with either a laser or plasma rifles I forget which one.
Backpedal dropping down mines and using dynamite/explosive weapons.
If you feeling brave use the chainsaw found in vault 3.
Also, pointing out the obvious crippling the legs will make your job a lot easier
I recommend the chainsaw - it's most fun :)
Solution 3:
Improve your sneak skill and get a decent sniper rifle (or even a hunting rifle with a scope). Crouch in an area the Deathclaws can't reach and bask in the glory of your sneak attack criticals. This is a great way of clearing the quarry full of them, even in the early game.
That said, in the early game you may not be equipped to deal with the radscorpions and cazadors in the route to a safe area to fire from in the quarry. But if you can get past them, I believe you can also score some standing with the Great Khans who have an outpost up there.
Do not under any circumstances walk up to a Deathclaw intending to kill it close-range. It never works, unless your intention is dying.
Solution 4:
Cripple the legs, aim high. Use a high powered medium/long ranged weapon to take out the legs and then aim for the head/torso. Most likely you would be using a grenade launcher, missile launcher, or alien blaster. You can get the alien blaster by going to the NW part of the map, where an alien commander and two other aliens are guarding there downed ship at the top of the cliff. This can only be performed with the Wild Wasteland perk on. Otherwise a group of bandits will be there, one containing a Gauss Rifle.