With only a day I would focus on the Furnace Creek area, Badwater, Artist's Drive, Devil's Golf Course, Zabriskie Point, Natural Bridge, with maybe a trip to the Sand Dunes. If you arrive or leave via Death Valley Junction you might consider a sidetrip up Dante's peak for panoramic views, preferably early or late in the day. If time permits you might go thru Beatty the other way and visit Rhyolite.
- DL