Import DXF File Into Blender With Correct Scale
By Forrest Smith - Drempd.com
[Note: This uses the “Import-Export: Import AutoCAD DXF Format” Add-on]
When importing, set the scale to 0.0254. This seems to scale it correctly, and based on my initial explorations, it seems as though you can snap to the linework in blender without an issue.
Updated Note: So this works if the source dxf’s default units are inches. Usually though, I want to just do everything in feet, so the scale is 12x the amount above, 0.3048.