While this is installing where does Crossover steam install the games to ? Just so I can add mods etc.
Crossover installs files in Library/Application Support
If you go to manage bottles or the bottle control panel (somewhere in there) in crossover, there is an option to have it open a finder window to the c:/ root folder of the bottle and from there you can copy/paste save files, add mods, or do anything else you need.