California Trip

I recommend searching for "Yosemite" in this forum and go back in the archives to get recommendations for campgrounds outside of the park. The small towns of Midpine and Mariposa have some private parks. Also, Indian Flat has a park just outside of Yosemite. Not much to speak of as a park but convenient. Book as soon as you can as they will fill up quickly. You can stay there and drive your toad into the park. Once you find a parking place, ride your bicycles if you have them or take the shuttle to get around the park. Spring is when you see the awesome water falls but early fall is a nice time as well. Yosemite is always busy! If you come in Spring from the Eastern side of the Sierras, Tioga Pass could be closed due to snow as they don't keep it plowed/cleared. In that case, you would need to come into the park from the western routes. You can still get to most of the park and see its beauty. Have fun planning!
In respect to Sequoia National Park, I also like Sequoia RV Ranch in Three Rivers.