QGIS was the workhorse for all GIS data acquisitions and manipulations. QGIS data outputs were an 'optimized' elevation raster, and OSM-based vector linework. A 3D model was then generated in Blender and exported to Fusion360 (when it was free) for tool-path generation. A Shapeoko XL milled the ~14x20x2.5in Ohio Valley yellow poplar stock. The wood burn linework was done by a custom 5W laser CNC attachment. Approximately a dozen were produced.

This project was done several years ago (~v3.4) and 3d capabilities have improved significantly since then. QGIS may be capable of generating an STL file natively now. I would probably still need Blender to refine the 3d model complexity for various terrain types.