Monster carnival PQ is the "new" thing to do now. They just introduced a Monster carnival PQ 2 for lvl 51-70 (i haven't tried that all too much) but yea for a brief lvling guide
50-64 MCPQ2
64-78 Windraiders in Crimson wood keep (check maps on how to get there)
78-85 Wolfspiders
85-95 Try Stormbreakers, firebrands or maybe even Temple of Time mobs? (not sure for a DK at this lvl)
95-128 Himes with a priest friend
128-200 Skelegon if you can get a bishop to train with you...otherwise...
128-200 Temple of Time Oblivion roads.