Write-in for LBJ. Even more than Kennedy, he was a space nut. Kennedy mostly just liked the soft power, from what I've read, while LBJ was a bit more of a true believer. If not for Vietnam...ah well.
I wonder if John Glenn will be Bobby Kennedy's VP in TTL. Glenn became very good friends with all of the Kennedies and with Bobby in particular. A successful RFK presidency might lead to a John Glenn White House.
I could see Wallace funneling a lot of money to the space program because of the fact that it would spur investment in Southern states like Texas, Florida, and especially his own Alabama.