This is a quick note on how to get RTree (0.9.7) and PyInstaller (3.4) to play nicely together, so that if you've got a script using RTree (e.g. for example, a script that calls trimesh.proximity.thickness()) that you need to compile into a .exe so that non-technical users can run it as a standalone binary without setting up a Python dev environment first.
These instructions are based on what worked on the project I'm working on, and are only tested with the versions listed on Windows 10. I haven't actually tested this on Linux, since most of the Linux users of this program are already doing a lot more coding work and will have dev environments set up anyway, that it doesn't matter for them.
Hopefully this helps someone else someday.