I'm in the same boat.

I will grind 62-65 in AV and maybe Underbog (first boss and reset).

My original plan was to bite the bullet and do Durnholde at 65 then grind Black Morass to 70+, should be easy to micro the boostees. Now I'm thinking at 63-65 it might be better to hit up Northrend and grind the uber fast repop mobs that attack the walls of the first quest hubs. These are 67-68 mobs that I can have my ungrouped DK pet assist on. I have no idea if it's worth it xp wise though.