Best Way To Grind Anniversary XP? (Mission Mods? Type? Open World Activities?)

I'm heading out on the 13th on vacation and won't be back till the 24th. I'm wanting to nail this season just in case I don't get time. But I just KNOW there's a quick, efficient way to do it in the meta. Any tips would be greatly appreciated (I run just under Heroic for most things. I think my build needs tweaking before I do any higher because the change is drastic when I up it)