Instead of putting an empty string here for the `gruntBaseDirectory` setting default value, I would think it would make more sense to use the `thisProject.value.base` value instead, since that is supposed to be the default.  It removes the need for a conditional later.

The `gruntNodePath` setting, for instance, only takes a string (as opposed to a file) because it does not have to be a file path, it could just be an alias or a short name.