In his journal for October 8, 1905, Anthony W. Ivins recorded Samuel W. Richards (1824-1909) sharing (albeit, late) reminiscences concerning the Saints moving to the Rocky Mountains and how the Temple in Independence (cf. D&C 84) would be built at the eschaton:
Sam[ue]l W. Richards said, he was intimate with the prophet Jos[eph]. In the winter of 1843 & 44 a messenger came and asked me if I would be one of a party to go and explore the Rocky Mountains, with 23 other men, to find a place where the Church could be established. He [Joseph Smith] relating a vision in which he saw the vallies of the Mountains, California & Northern Mexico, & then the building of a temple at Jackson Co. [Missouri] & the earth redeemed and filled with towns & villages & producing all that was necessary for the sustenance of man. (Anthony W. Ivins, Journal, October 8, 1905, in Cowboy Apostle: The Diaries of Anthony W. Ivins, 1875-1932, ed. Elizabeth Oberdick Anderson [Salt Lake City: Signature Books, 2013], 362-63)
Further Reading:
Resources on Joseph Smith's Prophecies