Can you describe in more detail what you want to accomplish? WP will normally redirect any alternative URLs to the URL set in its home/site URL settings, so any alternative URL scheme will take some effort. WP will also consistently add noindex meta tags to all pages when the discourage search bots setting is set, so again, some effort is required to do otherwise.
Some SEO plugins will let you selectively set noindex without needing to mask URLs or take similar measures.
