The question is not clear. There is no ‘default’ folder to access system files. All files remain in their original locations (but only certain locations are accessible when in the recovery console), and system files will be in the same location that they are when outside the recovery console, so the ‘default’ folder for system files is not related to the recovery console itself.
Inside the recovery console the SYSTEMROOT command can be used to set the current working directory to the %SystemRoot% folder of the windows installation (although you will be located at that folder when entering the recovery console by default).
If you are asking where the system files are you can always
or browse to C:\Windows
that’s where windows keeps it’s OS files.