I'd do it the other way about: mine the iron and get an iron mace and banded shield (say) before tackling Bonemass. Personally I went from Troll Armour to Iron Armour as soon as I could and skipped Bronze but that was before they introduced Root Armour.

Once you find a couple of crypts, getting enough iron shouldn't be a problem other than transporting it to your smelter.

All I did with bronze by way of kit was to get a bronze mace to tide me over until I could get an iron one.