At a recent Goldwater Institute event centered around the recently-released Pure Goldwater, Mike Renzulli asked Barry Goldwater Jr. and John Dean whether they had found anything in Barry Goldwater's correspondence about Ayn Rand—mispronouncing her name no less. Both tenatively answered (question and answer starting at 9'40") that they hadn't and that they didn't think he was aware of her.
That's been stewing in the back of my mind for awhile. Ayn Rand explicitly supported Goldwater in 1964 (The Objectivist Newsletter, vol. 3, no. 3, March 1964 and a wrap-up in vol. 3, no. 12, December 1964). Her marginalia, letters, journals, and Q&A sessions have all been made available so I decided to find out for myself.
It turns out that there was quite a bit of material on Goldwater by Ayn Rand. It started with a letter from him to her dated May 11, 1960: "I am particularly proud of the fact that you were the one to [defend my conservative position on Mike Wallace's show], because I have enjoyed very few books in my life as much as I have yours, Atlas Shrugged." She responded to him at considerable length on June 4, 1960 (Letters of Ayn Rand, pp. 565-72), taking him to task about Conscience of a Conservative, which he had sent her. In the margins of that book, she wrote three pages worth of notes along the same lines of her letter. (Ayn Rand's Marginalia, pp. 183-8) She also answered three questions about him at a lecture. (Ayn Rand Answers, pp. 58-9)
There was clearly a mutual regard between the two, but their philosophies couldn't have been more different and they weren't the fellow travelers one would have hoped.