You are right about camping outside most of these parks. In fact just driving a truck in some can be challenging due to crowds. Corona policies have caused limited access to some but that could change often. Yosemite has a good bus shuttle program so you can park outside and shuttle around.
Hwy 395 to Carson is good. We did it in November when we left CA for good. Enjoy the trip. Nice itinerary just be prepared for crowds and expect to see some of the best sights of God's creation.
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