Old school dailies on the isle. I think they give 10k xp each at 77 (could be wrong) and take little time to do. Northrend dailies that are multi-boxer friendly (I'm trying to help you get your gold for your cold weather flying). But if you want pure grind, I'd suggest you went with the highest level dungeon your group composition can handle. At 77, I'd look at OK, DK and then VH. If you don't want to instance grind, based upon what you've said your primary gather professions are skinning and mining.. so I'd suggest Scholazar Basin since nearly everything in that zone is skinnable and there's plenty of Saronite along the mountains. I'd stick mostly to the southwest corner of the map.