The way I killed the cazadors is got the lance from the secret underground bunker and then went on the rampage whereever I knew there was cazors, kills them instantly especially if you chose the extra 50% hit rate at the end of the level skill.
Not killed any Deathclaws yet apart from the odd one I found walking around in the pass that was blind, killed another at the quarrey with the lance also but the pack where too strong at once so ive left them for now.
stuck on what to do for Mr Lucky at Hoover dam, just running around trying to find out what to put his memory chip in and I can't leave till I do it. Killed the picked jar fellow Mr house so now Mr Lucky is the boss at the strip, killed all the masked guys and the mobsters at the other casino too in fact I have more or less killed everyone at the strip except Mr Lucky and the now robots that have turned into soldiers and shoot rockets