I would do a mix bag.
Do all the dungeons a few times, but make sure you do quests as well.
maybe focus on some important questlines, like the wrathgate at your level.

Since you're with heirlooms, you can afford to skip all the annoying quests as you'll out level the regions quickly.

definitely do the random dungeon everyday to build up a stack of triumphs,. that and the BG.