David Whitmer, the last surviving witness to the Book of Mormon, lived until 1888. He spent most of his adult life outside of the Church of Jesus Christ of Latter-day Saints, but never denied — in fact, often reaffirmed — his testimony of the book.
Here are some passages from his account, as reproduced in Hyrum L. Andrus and Helen Mae Andrus, Personal Glimpses of the Prophet Joseph Smith (American Fork, UT: Covenant Communications, 2009):
David Whitmer explains that he first heard of what would eventually be known as Mormonism in the 1828, when, during a business trip to Palmyra, New York, he heard people talking about certain golden plates allegedly found by a young man in the neighborhood.
I had conversation with several young men who said that Joseph Smith certainly had golden plates, and that before he had attained them [while he searched with them, for a time, for lost treasures] he had promised to share with them, but had not done so and they were very much incensed with him.
Said I, “How do you know that Joe Smith has the plates?”
They replied, “We saw the place in the hill that he took them out of, just as he described it to us before he had obtained them.”
These parties were so positive in their statements that I began to believe there must be some foundation for the stories then in circulation all over that part of the country. (41)
After several months Oliver [Cowdery] told me he was going to Harmony, Pa., whither Joseph Smith had gone with the plates on account of the persecutions of his neighbors, and see him about the matter. He did go, and on his way he stopped at my father’s house and told me that as soon as he found out anything, either truth or untruth, he would let me know.After he got there he became acquainted with Joseph Smith, and shortly after wrote to me tell me that he was convinced that Smith had the records, that Joseph had told him his (Oliver’s) secret thoughts, and all he had meditated about going to see him, which no man on earth knew, as he supposed, but himself. Smith told him that it was the will of heaven that he (Oliver) should be his scribe to assist in the translation of the plates, so he stopped to write for Joseph. (41-42)
Soon thereafter, Oliver Cowdery wrote to David Whitmer asking him to come down to them in Harmony and to take them back up to Fayette, New York.
I did not know what to do, I was pressed with my work. I had some 20 acres to plow, so I concluded I would finish plowing and then go. I got up one morning to go to work, as usual, and on going to the field found between five and seven acres of my ground had been plowed during the night.
I don’t know who did it; but it was done just as I would have done it myself, and the plow was left standing in the furrow. This enabled me to start sooner. (42)
When I arrived at Harmony, Joseph and Oliver were coming toward me, and met me some distance from the house. Oliver told me that Joseph had informed him when I started from home, where I had stopped the first night, how I read the sign at the tavern, where I stopped the next night, etc., and that I would be there that day before dinner, and this was why they had come out to meet me; all of which was exactly as Joseph had told Oliver, at which I was greatly astonished. (42)