I was hoping for a better outcome of course. Very sad. I've never explored this part of DV so I read up a bit here.
Craig, here's a link to information on a descent of Willow Canyon -
and these three did not want to do the loooooong shuttle so ascended the north ridge from the bottom and dropped into Willow canyon at a mid point.
Our last trip in the area was April 2012. Here's the end of Gold Valley Road at willow Springs, view up canyon.
You cannot see down into Death Valley from this area. Willow Springs is a thick riparian jungle.
You can venture down Willow Canyon for around a mile before the terrain turns technical. Of course, we have no facts on where the couple was found; everything I could offer is speculation, assumptions, and an exercise in typing.
If any here get the crazy idea to descend down into Death Valley, find a pass/saddle to the north and drop into Sheep Canyon, one of the easier canyons in the Black Mountains.
Before doing anything in Death Valley get a copy of Hiking Death Valley and read it.