The quickest and most convenient route from Yosemite to Death Valley is via the Tuoleme Pass near Yosemite. It is also a very scenic route with a number of attractions along the way. You can visit Mono Lake, the ghost town of Bodie and the Inyo National Forerst along the way to Death Valley.
Unfortunately, Tuolome Pass closes from late October until May every year due to heavy snow accummulation. If you want to take this route you must visit during the Summer months or early Autumn. That is not the best time to visit Death Valley as it will be very hot during the Summer. Winter is the best time to go to Death Valley.
The most convenient places to stay are at the park hotels located within Yosemite Valley. These accommodations are usually fully booked many months in advance. If you want to stay there, you should make reservations six months to one year in advance. Fortunately, there are many choices of accommodations located just outside of the park. Check our USATourist.com page on Yosemite accommodations for suggestions.
In Death Valley, there are few accommodations; only the motels in Furnace Creek and Stovepipe Wells. There are almost no other accommodations near this desolate park. The closest ones outside of the park are nearly an hour drive away. I suggest you stay in Death Valley, but make your reservations early. (At least 3 months in advance)
There is not much left of old Route 66. Most of it was replaced by interstate highways over forty years ago. The largest remaining segments of the old road can be found between Kingman Arizona and Seligman. This is about three hours drive south of Las Vegas.
There are Native American "Indian Reservations" at many places in California, Nevada and Arizona. There is a small Indian settlement near Furnace Creek in Death Valley. You won't find much to see in most Indian communities, as they look just like any other community in the area. I suggest you go to a reservation where the tribe has constructed a visitor's center or a tourist attraction. The West Rim of the Grand Canyon is owned by the Hualapai tribe and they have created a flourishing tourist attraction including a glass walkway suspended over 1.000 meters above the gorge. They also have replica dwellings including tepees, wigwams and hogans. They provide authentic tribal dancers to entertain visitors.