Best things to do on the way to Sacramento CA from San Antonio TX?

Unfortunately, you've kind of tied yourself down by saying you want to spend time in L.A. In order to get from San Antonio to Sacramento and stop in L.A. on the way, you don't have time to see much else in 6 days. If you want to see some more nature sites (like the Grand Canyon, Yosemite, etc.), you would have to leave L.A out of the picture. Draw a line on a map from Texas to Sacramento. It does not go through L.A. Going there is going out of your way, and you will have to trade extra driving for extra sightseeing.