if you are attacking iron/steel dragons with ranged attacks, will they approach you and melee you? or stay at range and breath on you? i dont remember

also; what are some other good monsters to train ranged on (caged ogres are not as good as i remember them being), besides the avians in gwd?

Well, if you want cash those fuckers in GWD are going to be your absolute best bet.

As for the metal dragons, Irons+Steels will only attack with the breath attack if you are more than 1 square away. They will never come up and melee you. Just pay attention though because it is easy to die there if you don't pay attention.

If you want just range xp in general, I would do Slayer and use a cannon + xbow with broad bolts on my tasks, but thats just me.