The Huntington Library is a hidden gem in San Marino, CA. If you have never been, the Desert Garden alone is a must see. Your visit definitely does not need to be an all day event; however, there are some great picnic spots and places to hang out and relax. My advice, do not op for the Rose Tea Garden. It sounds like a perfect idea but the price coupled with the food and cramped space is not worth it. If anything, spend time walking outside and visiting the galleries. There is the infamous Blue Boy by Thomas Gainsborough and also now, Pinkie by Thomas Lawrence. You can try to get free tickets for the first Thursday of the month or just find a date that fits your schedule the best.
Anyways, here are some of my favorite pictures from the Huntington Library. Doesn't the scenery remind you of Jurassic Park??