RODNEY CROWELL, the talented Houston-born songwriter who began recording in the late seventies, has followed an uneven road to success. At times he’s sounded adrift or bored, trapped by the “progressive country” parameters he imposed on himself. But starting in 2001, something clicked. First came The Houston Kid , followed by Fate’s Right Hand and now The Outsider (Columbia), and with them, Crowell has an assured new voice. Pointed and witty, his latest album shuns the hokey arrangements from his early work in favor of a solid, no-frills rock and roll base. His former mentor Emmylou Harris tugs him back to old Nashville for her contributions, but overall the album is remarkably focused. Most people are slacking off at this point in their careers. Crowell sounds as if he’s just getting started.