I solved the level and attached my replay below. (I saved 37/40 8-))
Was a nice level and definitely tough to figure out how to separate workers to go on ahead and construct parts of the level. It seems like the level is a little open ended so I doubt my solution is a backroute (or an unintended solution), but you never know ;)
P.S.: I noticed you're new here, so I want to welcome you to the forums! :)