I did not know there was a reddit on the Campaign Trail, but there is, and yes people have figured out how to produce their own scenarios. I followed the admittedly complicated instructions on how to port the relevant code and was able to play 1964 as Goldwater.
The problem was that the questions weren't very good. I think doing these scenarios right takes a lot of time, and you really need to get a history nerd to work together with a computer nerd who can code. However the scenario was playable.
I switched to a pro-civil rights legislation position and emphasized the more libertarian aspects of Goldwater's platform. I would have liked to be able to pick a different running mate than William Miller, but going to the wikipedia page on the election, the only alternative I could find would have been Walter Judd, who sounds like he would have been worse. The problem is that Goldwater's choices for running mate were really limited and Miller actually wasn't that bad as far as modern VP candidates go.
I carried the six states Goldwater carried (Arizona and the Deep South), despite backtracking on civil rights, plus Indiana and Utah, but the national popular vote percentage margin was worse for Goldwater, 33.8% instead of the historical 32.5%. However, this seems to have been an artifact of the scenario developer not accounting for minor party candidates. In the actual election, they got just under 0.5% of the nationwide popular vote (0.3% for a slate of unpledged Democratic electors in Alabama), but I also ran 0.4% behind Goldwater's nationwide popular vote percentage. I did this on Normal.