Where do you start from and how long will leisurely hike take down Fall Canyon? Would 7AM be advisable starting time?

We plan to drive through death valley in 2 days first week of this June. What "must see" places would you recommend to optimize us of time? We are three outdoor types ready to camp anywhere though we prefer site with shower facilities.

Your trip suggestions are great. However, I question the idea of hiking into Fall Canyon after lunch in the summer. That was the game plan my wife and I had, but it was 115 degrees F at 11:30 A.M. We bagged that idea and went to Ubehebe Crater where it was a little cooler (95 to 100 degrees) with a steady breeze blowing on the rim. We realized that the game plan for hiking in Death Valley is to hike low early and if planning a second hike, make sure it is at a higher (cooler) elevation.