Wawona and Mariposa Grove is another area in Yosemite you should not miss. In Mariposa Grove you will see the big sequoias, and in Wawona the Wawona Hotel, from the 19th century, and some historic buildings.
Although you can go to this area the same day you visit Yosemite Valley, it is better staying a night in the Valley, and going to Mariposa Grove the next day. The area is a 40-minute drive from Yosemite Valley. You can leave your car in the Wawona parking lot, and get to Mariposa Grove by the free public shuttle bus, or walk the two miles.