Fully upgraded iron armor is about as good as silver armor baseline and you should be able to handle plains mobs somewhat alright with that. If not, I’d recommend just heading up into mountains and searching mountain tops for silver. You won’t be able to find all the nodes, but it isn’t too hard to get silver without the wishbone. My buddy and I had close to 300 silver pre-bonemass and had two more nodes marked but not mined still to hit. We only searched three mountains.

Just skip him for a bit and get yourself some silver gear. The Frostner hammer is probably the best weapon for fighting bonemass anyway.