Personally, I level on the critters in 4 winds on the vermin free farms. I have leveled a few toons this way, currently leveling a monk which is up to 72, started at 23 there. My go to team was spec porc, xu'fu and leveler, using spectral barrier, switching in leveler, then xu'fu to kill them. Currently, I use Murkalot in place of spec porc, sheild storm for the win!
<Kings and Queens> Alliance on Dawnbringer
-pet collecting OCD