Welcome to FT, Walter!
There is no good month to do both Sierra Nevada parks and desert parks. It'll either be too wintery in the mountains or too hot in the desert. There are bus tour groups that do this sort of thing. It's really stupid. Visiting these parks should not be something you do in a hurry just to say you have been to them.
Given that you are planning to allocate just a bit more than one day to Death Valley, I'd suggest skipping it on this trip. Do Sequoia and Kings Canyon instead and save Death Valley for a future winter trip.