While I would deeply, deeply love to report otherwise, a 2011 Macbook air is not the computer to use if you want to layer modern hillshades with vintage maps in Blender. After many fruitless hours trying, this is my best shot using QGIS alone.
I’m not entirely satisfied with the results. They’re a far cry from the soft light and gentle shadows I had been hoping for. Still, I think the results are decent given that everything was done in QGIS. You can read the full write-up for this project here.