I failed pretty miserably in UK, but I can farm the snake and mammoth bosses in Gundrak pretty easily. As soon as I get exalted with Argent I'll get a pretty nice ring for the shammies which is a good upgrade, maybe after that I'll go kill the collussus and last boss. In UK, each time I tried Keleseth, he aggroes before I'm really set up, so it's a losing fight to begin with.

For the snake guy in Gundrak just park your clones in the entrance hallway, pull the snake guy to the edge of the stairs and go to town. For the mammoth guy, make a macro like

/stopcasting
/cast Earth Shock

every time he starts to transform. Once I did that (didn't have /stopcasting before, so it would usually fail) he's pretty much cake.