I'm not sure if u can specify cheat options as a startup from a menu link. I don't think there is support for the in game console either. but quake runs a script or a few upon startup that i think you may get away with putting cheats into? or bind a button to a console command through default.config ??? something like that neway.
im guessing the usual commands like go and noclip, u should be able to google them easy enough.