When you get to the mists, just keep jumping to move forward quickly and the Urgals shouldn't be able to get you. If they catch up and knock you down, fire a magic arrow to knock them to the ground and continue your kangaroo quest out of the mists. In the next section, there is one pressure plate right in front of you, the other is in the back left corner of the mists, up on a ledge. For the final battle, try to knock as many off the cliff as possible and use the magic arrow+stab combo to make it go quickly.