In my opinion, you'll be very sad after your one day of shooting. Try to spread it out at least for two full days of shooting.

On Day 1 take the valley floor tour. They stop at most of the hotspots. Take a small or medium format camera with you on the tour. Take mental notes of the places you'd like to return to.

I wouldn't worry about the people getting in the way. What I have done in the past is get up at the crack of dawn and start driving to the locations I want. Most tourists are still asleep.

Have fun, I'll be up that way at the end of August.