Willie Nelson, Jessica Simpson and other stars of The Dukes of Hazzard are embarking on a brief USO tour of military installations in three states. Johnny Knoxville and Seann William Scott will join Simpson for a July 26 visit to Robins Air Force Base, Ga., followed by and a July 27 trip to Fort Hood, Texas. Nelson and Simpson are scheduled for a July 29 stop at the Marine Corps Air Station in Miramar, Calif. The cast members will spend time with the military personnel and host a free screening of the movie that hits theaters on Aug. 5. Nelson portrays Uncle Jesse in the film that also stars Burt Reynolds.