I don't disagree with ANY of the ideas above, all are relevant and have advantages disadvantages; This is my 'Super-secret spot' I was training ranged at flesh crawlers. (Which is mediocre exp, and boring but you don't have to pay 100% attention) Ended up killing zombies and they were brilliant. You got back a lot of steel arrows, and no drops are breathtaking, but it's consistent exp which is fairly fun. (It's faster than giants, probably even lessers and is quite a lot more fun) There is a room with only zombies. (I think L30, but don't hold me to it.) It's good exp at my level, but I bet at yours it would be excellent. Go ahead and say any feedback you have after you've trained there. (If you decide to do so)