I think this would be a great timeline. Lyndon B Johnson was a great man, who deserved his presidency to work out in otl.
Well he certainly had bad luck, but to be fair Vietnam was largely his fault. He deliberately turned around Kennedy's less interventionist ideas in favor of direct committal of ground troops-though to be fair fair, Congress was totally behind him (I believe the Gulf of Tonkin Resolution had two opposing votes in the Senate) and his Cabinet was in favor of interevention. And Diem had already been kicked out, so things were already going downhill.