Stronghold of security is always a good place to train. But if it does get a little dull, I recommend you try out Armoured Zombies. They require partial completion of Curse of Arrav to get to, but being undead, salve amulet is very useful. Also, up a ladder only a few steps away is an altar to recharge prayer for more bonuses. Very useful for dealing high hits frequently and getting lots of experience. I can manage to get around 65-75k xp per hour at Armoured Zombies, and only 50-60k per hour in stronghold.
Oh and that's assuming you are p2p.