peachygirl,
Not at strange choice to my mind; my brother once paid a visit to that museum!!.
Nixon's library is at Yorba Linda; the directions for which are given below:-
From DOWNTOWN LOS ANGELES: Go south on Interstate 5 to Highway 91. Take Highway 91 east to Highway 57. Take Highway 57 North and exit Yorba Linda Boulevard. Head east (turn right) on Yorba Linda Boulevard and proceed to the Museum at 18001 Yorba Linda Boulevard.
www.nixonfoundation.org is the website to look at and has all sorts of information.
What part of LA are you staying in?. I ask this as if you're staying in the Hollywood area you can get the Metro train service up to Universal. If you're staying somewhere other than Hollywood you'll need to book an excursion or drive.
SF is nice and there's good shopping around Union Square in particular - Macys is v good for shopping along with Nordstrom (my fave department store!). Fishermans Wharf area is touristy with some nice restaurants (Bubba Gumps is good) but you can get boats from there to take you across to Sausalito and other places.
Do consider a trip out to the Grand Canyon when you;re there.
Would recommend you see the Forum shops at Caesars Palace, pay particular attention to the sky in there and the fountain of Bacchus!!. Spagos (for lunch) is excellent. Hoover Dam is worth a trip out and is not too long a journey. Haven't stayed at the Stratosphere Tower but have been inside the casino and it looked perfectly fine.
Hope you have a fab time!!.