[_ck_]

If you are on a host with a menu based system like Cpanel or Plesk they usually have an option to password protect a directory. You can use that to protect your bbpress forum install (and wordpress) and that way it will be impossible to access for anyone except you.

There is a bbpress plugin that forces login to be required to see the forum so you could install that and even if anyone found it, they would only see a login.