FYI: This no longer works now that the frontend form is submitted via ajax. In order to redirect to the post, you need to do something like this:
// Redirect to the newly created post
add_action( 'rwmb_frontend_after_process', function( $config, $post_id ) {
$url = get_post_permalink( $post_id );
echo json_encode(
array(
'success'=>true,
'data'=> array(
'message' => 'Your success message',
'redirect' => $url
)
)
);
die;
}, 10, 2 );