Dinesh Desai did it over a 12 day period in 1998 and it is chronicled
on this web site.
"The Great Daring Stupendous Unbelievable Dinesh Death Valley Trek"
"Here, then, are the unexpurgated, never-before-published chronicles of
Dinesh's walk across Death Valley. For 12 days. In the middle of summer."
Not a casual walk to make, as shown in this Palm Springs, California
"Desert Sun" news article.
"Death Valley trekker found dead of exposure"
"A 35-year-old man was found dead of apparent heat exposure after he tried
to walk nearly 20 miles across Death Valley National Park carrying parts
and supplies to repair his vehicle, officials said Thursday."
If you need any clarification, please feel free to ask.
Google search on: "Death Valley" "walk across" OR "hike across"
Looking Forward, denco-ga - Google Answers Researcher