This Cairne Bloodhoof deck is excellent for all dungeons and PvE alike. You will deploy an extremely fast Cairne Bloodhoof that can usually handle its own. Supplement with versatile units to push in a lane and get to the boss. Once at the boss, drop Whelps, nuke with S.A.F.E Pilot, and send in the Harpies. GG.
Stonehoof Tauren: Solid tank that destroys squishy ranged units.
Darkspear Troll: High damage ranged Horde unit. Can swap this out with another mini like Frostwolf Shaman.
S.A.F.E Pilot: Extremely versatile mini that provides AoE damage, extra nuke damage on the boss, and the ability to snag chests for extra gold
Quilboar: Cycle/unbound mini that can tank towers or take aggro right before your Harpies get to the fight.
Whelps: Whelps with Flame Burst are great. Use them to either take out large groups of ground units, or to nuke a boss. Couple with the Quilboar and S.A.F.E Pilot for some quick boss killing action.
Harpy: Harpies are the main damage dealer. An unchecked group of Harpies with Poison deals insane damage against units, towers, bosses, and anything inbetween. A strategy I like to use is to summon a Quilboar immediately before a Harpy engages, so it takes aggro while the Harpy can dish out the DPS.
This deck can clear Dungeon Level 22 for a full gold deck. You may run into issues if you are under-leveled for the content you are trying. I would spend gold leveling up Stonehoof, Quilboar, Whelps, and Harpies, as these units are used in many decks, regardless of leader.