See the actual 1964 results...maybe with a flip in Utah, Idaho, and Florida.
I disagree , Reagan being a two term governor of California will be significantly more electable than a Right Wing Senator of Arizona.Goldwater who spent nearly all his time in the Senate in the opposition, is much easier to attack than Reagan. The reason for that is because when the Democrats attacked Goldwater for being an extreme right wing nut job , it worked in large part due to him not implementing his policies in a state , or being part of the majority party in the senate for a significant part of his career. For Reagan if they try that attack , he can just bring up the economic numbers during his time as Governor and say the polices you are calling extreme have proven to work in the largest state in the union .
I think it's already been mentioned, but Reagan wasn't governor in '64. He became governor in '67.