Nah, Gold and Copper Bars are the way to go. It's just like a big part of the game so I thought it should have a big quest objective. The bars double up as metal though, so if you use those you really only need to fill in 60 of some other metal. Steel is worth the most, but Gold would be the fastest to produce.
The out of bounds stuff is a little embarrassing! When I redid the tilesets, I missed a collision box in there, they're all getting fixed though.