While indelibly linked with the role of the somewhat naive would-be writer John-Boy Walton in the CBS drama series "The Waltons" (and its spin-off TV-movies), Richard Thomas has had a richly diverse career that has encompassed stage, screen and TV.The son of ballet dancers, Thomas began his career as a juvenile performer making his Broadway debut at age seven as one of the Roosevelt children in the award-winning play "Sunrise at Campobello" (1958). Additional stage roles followed including John Henry in "The Member of the Wedding" (1959), Eric in "The Playroom" and the two young princes killed