Richard de Mille demonstrated that Castaneda's work was a hoax. He lifted entire passages from other authors such as C.S. Lewis. The Indian tribe that he supposedly apprenticed under never used peyote.
If you think you can master his material and jump off a cliff and survive as he claimed to do, please do so.
His female followers disappeared into the death valley area after his death. I believe their bones were found, so apparently they didn't escape death either.