It doesn't make much sense to compile yet another physics engine for an open source game engine which ships with an internal physics engine already... But I end up doing it anyway...
The c# files are generated by swig, but needed some manual fixing. Swig seems to generate a few "override" handle where it shouldn't, and the swig config file that comes with Project Chrono is supposed to fix that automatically (but didn't). Anyways it seems to work fine after the fixes, at least for simple test cases with simple hardbody and softbody collision.
To use the compiled library, simply copy everything into the root folder of the Godot(mono) project. You should be able to include the c# classes straight away.
If I have additional time and energy I might consider adding demo scenes for simple collisions and the vehicle module.
altyee