He had moved to New York after the 1962 defeat and was really out of the California scene by 1966. It turned out to be a good move for him and family--made plenty of money in his law practice and book writing and was a regular on several talk shows--mostly in New York at that time.
He did a lot of campaigning for GOP congressional candidates in the 1966 midterms, in which they picked up 37 seats after 1964 landslide defeat. That played some role for Nixon to win the nomination 4 prez again in 1968.