Good research. Put it up on twitter to see if people run with it.
Neither of Nixon’s daughter’s weddings were in California.
Julie was married in New York City in December, 1968.
Tricia was married in the Rose Garden in (I believe) 1970 or 1971.
I am embarassed to admit, that I do not have a Twitter account.
I screwed, I researched this matter again, and actually it is much more common for the President to spend Christmas elewhere. For instance, LBJ spent everyone one of them at his Ranch.
I would say, the President President Reagan, H.W. Bush, and George W. Bush,are the only ones that spent every Christmas in Washington D.C.