Right now I'm dual boxing 2 DKs (blood & Unholy) and its going pretty fast. I haven't spent much time dead but it is a lil hard without a healer. If I were you I'd team him with at least 1 of the shammies for heals, group or not. If in group with only one shammy, that will keep the xp per kill up. If not in group make sure the DK strikes first blow on targets to get credit for the kills. Just use the shammy as a back up for heals and emergencies. The Death Knight can crank out a lot of dmg, and with a descent healer you shouldn't die much at all if any. Once you learn to play with the DK, Outlands is pretty much a breeze.