The default paths for the indexes are stored on the system partition, more precisely in the following folder: C:\Users\YOURUSER\AppData\Roaming\Rummage. You can open it using:
%APPDATA%\Rummage\. You can't pause or restart the index procedure once it started. No, in the alpha version, the constant monitoring option is not available. You will have to manually update the index. The index files will remain in their location if the software is removed.