By CHARLIE LeDUFF (NYT) VICTORVILLE, Calif., May 27 -- A small yet not insignificant piece of news occurred in April while the world's attention was turned toward Iraq. The Roy Rogers-Dale Evans Museum, an old-West cavalry-style fort on Highway 15 in the high Mojave Desert, picked up and moved. It has resettled in Branson, Mo., the transplanted heart of country-western life and culture. The move was economic, said Victorville city fathers. Fewer and fewer people, it seems, are interested in the life of the ''King of the Cowboys'' or his wife, Dale Evans, known as the ''Queen of the West.''...