On my MiKTeX 2.9.7206 installation, the MiKTeX console has a drop down menu that lets me update font map files in Admin more, but it does not give me any option to update in User mode. What folder must I get into to run font map files update in User mode?
Frame challenge: you almost certainly do not want to update your font maps in user mode. That’s a trap. It will appear to work in the short term, but break your installation more and more over time.
If you’re asking this question, you have an XY problem, such as, “I downloaded a custom 8-bit font and now I need to install its font map.” The solutions to that real problem include: adding a local directory to your installation, or using an OpenType or TrueType version of the font in LuaTeX.