As for Big Sur and Redwoods, that would add a week to the OP's trip.
Perhaps if the OP is taking this trip on a bicycle. But if in an RV the time driving distance between Yosemite and Lake Tahoe is three hours; add another five hours or so and you can be in Big Sur. Six hours north of Big Sur are the Giant Redwoods. As mentioned above Zephyr Cove is a nice Tahoe campground, easily walkable to the Lake and a restaurant.
If you run into issues getting a reservation in Yosemite there are places just outside the park that are usually easier to acquire. Mariposa has a nice fairgrounds with RV hookups for a reasonable price. It is about 45 minutes to Yosemite.
Of course it all depends on how many days the OP plans to stay everywhere. That could add a few days to weeks.