questions on where to start -- 70 hunter

I have a 70 hunter already, and a 70 rogue i could use, but don't really want to bring the rogue, i'd rather use the hunter, it's better geared incase of pvp

i have a priest i'm trying to level and she's already level 41 due to questing. now im new to dual boxing. so curious if i should grind straight up in dungeons with the hunter or if i should quest it out with the hunter

i've read both things, but nothing strictly class related. or multi account related.

any ideas?

Since you are just power leveling one toon and not a group.. Quests are the way to go. Collection quests wouldnt even be that bad just have your Hunter blow through and your Priest loot. Do the instance quests when you get tired of the other stuff. After the last patch to make quests give more exp its a great way to lvl.