Access denied messaging and behavior
You can do it in hook_views_pre_render() like this:

/**
 * Implements hook_views_pre_render().
 */
function MODULENAME_views_pre_render(&amp;$view) {
  if ($view-&gt;name == 'VIEWNAME') {
    if (!user_is_logged_in() &amp;&amp; !empty($view-&gt;field['FIELDNAME']-&gt;options['alter']['path'])) {
      $view-&gt;field['FIELDNAME']-&gt;options['alter']['path'] = 'user/login?destination=' . $view-&gt;field['FIELDNAME']-&gt;options['alter']['path'];
    }
  }
}


Where in this case I would say 'title' is your FIELDNAME.

This will, if the user is logged out, replace whatever you have for your link in the rewrite settings, with a link to the login page, with your original path as the query destination, which will be used to return you to that page after the login form is submitted.

Also, there is the modal_forms module, which might be worth trying for a pop-up solution.  However then you need to take them to the comment reply page after the modal form closes.