You can raise ground to where you need your fire to sit and carve away anything you don't need. You can place the fire outside of your main structure (just outside) then build a wooden chimney using the wall pieces. Use the longer pieces of reg wood vertical as a stand-off and put a 45 degree apex roof piece over the hole. you can build it around one wooden floor tile or two, if you place the "seems" of the walls facing out.

When doing a chimney you need at least 1 floor tile of unobstructed flow above the fire for vent.

Or if you make ceiling high enough you wont need to vent smoke and you can place the fire in the center (again raise ground to wherever you need fire to be)