Layout Smelting with all three furnace types on the grid with reserved roadways. Also put in some long hand inserters for coal only on one layout.
This blueprint is intended to be copied a few times and have players remove the blocks they don't need. This way it contains various options that snap together differently.
In the example bus feeding, the top bus would be coal, and the bottom one either iron or copper. Steel smelting is left as an exercise to the player.